Embedded high voltage transformer components and methods

ABSTRACT

Disclosed are apparatus and methods for embedded high voltage transformer components. Industrial applications require transformers that provide high voltage isolation. The laminate materials used for fabricating Printed Circuit Boards (PCB) are very good insulators and PCB transformers can provide higher voltage isolation than traditional wire wound devices. There are a variety of PCB laminate materials with different properties for voltage breakdown. FR-4 laminate is commonly used and has voltage breakdown properties exceeding 10 kV/mm. To produce PCB transformers with breakdown voltages exceeding 5 kV, it is beneficial to use laminate with much higher breakdown voltages. Generally, the materials with high breakdown voltage cost more. High voltage isolation can be achieved at a moderate cost by mixing low cost FR-4 laminate with high voltage dielectric materials.

PRIORITY APPLICATIONS

This is a continuation-in-part (CIP) application of and claimingpriority to U.S. non-provisional patent application Ser. No. 16/102,039,filed on Aug. 13, 2018; which is a continuation application of andclaiming priority to U.S. non-provisional patent application Ser. No.14/963,619, filed on Dec. 9, 2015, now U.S. Pat. No. 10,049,803; whichis a continuation-in-part application of and claiming priority to U.S.non-provisional patent application Ser. No. 12/329,887, filed on Dec. 8,2008, now U.S. Pat. No. 9,355,769; which is a divisional application ofU.S. non-provisional patent application Ser. No. 11/233,824, filed onSep. 22, 2005, now U.S. Pat. No. 7,477,128; U.S. non-provisional patentapplication Ser. No. 14/963,619 is also a continuation-in-partapplication of and claiming priority to U.S. non-provisional patentapplication Ser. No. 14/891,645, filed on Nov. 16, 2015, now U.S. Pat.No. 9,754,714, which is a U.S. national phase application ofPCT/US2009/052512, filed on Jul. 31, 2009.

This is also a continuation-in-part (CIP) application of and claimingpriority to U.S. patent application Ser. No. 16/016,576, filed on Jun.23, 2018; which is a divisional application of and claiming priority toU.S. patent application Ser. No. 15/168,185, filed on May 30, 2016;which is a continuation-in-part patent application claiming priority toU.S. patent application Ser. No. 12/329,887, filed on Dec. 8, 2008, nowU.S. Pat. No. 9,355,769; which is a divisional application claimingpriority to U.S. non-provisional patent application Ser. No. 11/233,824,filed on Sep. 22, 2005, now U.S. Pat. No. 7,477,128.

The entire disclosure of the referenced patent applications isconsidered part of the disclosure of the present application and ishereby incorporated by reference herein in its entirety.

FIELD

The disclosure generally relates to magnetic devices and magneticcomponents having winding-type electrical circuits.

BACKGROUND

A wide range of electronic devices may have various magnetic components.Magnetic components may be capable of providing various functions. Forexample, magnetic components in electronic devices may function astransformers, inductors, filters, and so forth.

Commonly, in order to have magnetic properties, magnetic components maycomprise an assembly of one or more wires wound around a material havingpermeability properties such as ferromagnetic material having a toroidaltype shape, a rod type shape, etc. When a current is applied to the oneor more wires, the component may produce a magnetic field, which may beutilized to address a wide range of electrical needs associated withelectronic devices.

Higher power applications require a larger volume of ferromagneticmaterial to transfer electromagnetic energy between the device windings.For high power applications, the winding thickness can limit the amountof current that the device can deliver. Apparatus and methods formagnetic components are needed to overcome these limits and providehigher inductance and power capability.

High voltage applications rely on the insulation properties of materialsthat surround the conductive windings. An electrical short betweenprimary and secondary windings can occur when the applied voltageexceeds the dielectric breakdown properties of the insulating material.Separation between the windings is also determinate factor whendesigning for a specific breakdown voltage.

SUMMARY

Described embodiments are directed to apparatus and methods for embeddedmagnetic components having winding-type electrical circuits and arrayedembedded magnetic components.

Embodiments of a magnetic component comprise a first magnetic deviceincluding a first winding pattern implemented as a first secondsubstrate conductive pattern, a first third substrate conductive patternand first plated through holes that are electrically interconnected withthe first second substrate conductive pattern and the first thirdsubstrate conductive pattern. The first winding pattern surrounds afirst core. The first core defines a toroidal shape and the firstwinding pattern defines a complementary toroidal shape. The firstwinding pattern defines one or more electric circuits that surround thefirst core thereby forming a winding-type relationship so as to induce amagnetic flux within the first core when the one or more electriccircuits are energized by a time varying voltage potential.

In other embodiments, the magnetic component further comprises a secondmagnetic device including a second winding pattern implemented as asecond second substrate conductive pattern, a second third substrateconductive pattern, and second plated through holes electricallyinterconnected with the second second substrate conductive pattern andthe second third substrate conductive pattern surrounding a second core.The second core defines a toroidal shape and the second winding patterndefines a complementary toroidal shape. The second winding patterndefines one or more electric circuits that surround the second corethereby forming a winding-type relationship so as to induce a magneticflux within the second core when the one or more electric circuits areenergized by a time varying voltage potential. The first magnetic deviceand the second magnetic device are electrically interconnected.

In other embodiments, arrayed embedded magnetic components include twoor more magnetic devices electrically connected in parallel or series orcombinations thereof, and positioned side-by-side in a horizontalintegration defining a horizontal array, positioned coaxially in avertical integration defining a vertical array, or combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings, in which likereferences may indicate similar elements and in which:

FIG. 1A is a perspective exploded view and FIG. 1B is a cross-sectionalexploded view about line 1B-1B of an embedded magnetic device inaccordance with an embodiment;

FIG. 1C is a cross-sectional view about cut line 1C-1C of the magneticdevice of the embodiment of FIG. 1A;

FIGS. 2A and 2B are top and cross-sectional views about line 2B-2B,respectively, of the base substrate 102 in accordance with theembodiment of FIGS. 1A and 1B;

FIG. 3 is a top view of the base substrate and the first conductivepattern in accordance with the embodiment of FIGS. 1A and 1B;

FIG. 4 is a perspective exploded view of an embedded magnetic device inaccordance with another embodiment;

FIG. 5A is a circuit illustration as a superimposed image of anembodiment of an embedded magnetic device including a base substratehaving a feature, a first conductive pattern, core, a second substrate,and a second conductive pattern;

FIG. 5B is a dual common mode filter schematic representative of thefunctionality of the embodiment of FIG. 5A;

FIG. 6A is a circuit illustration as a superimposed image of an embeddedmagnetic device in accordance with another embodiment;

FIG. 6B is a single common mode filter schematic representative of thefunctionality of the embodiment of FIG. 6A;

FIG. 7A is a circuit illustration as a superimposed image of an embeddedmagnetic device in accordance with another embodiment;

FIG. 7B is a single inductor schematic representative of thefunctionality of the embodiment of FIG. 7A;

FIG. 8A is a circuit illustration as a superimposed image of a magneticdevice in accordance with another embodiment;

FIG. 8B is an isolation transformer schematic representative of thefunctionality of the embodiment of FIG. 8A;

FIG. 9A is a circuit illustration as a superimposed image of an embeddedmagnetic device in accordance with another embodiment;

FIG. 9B is a three-wire common mode choke schematic representative ofthe functionality of the embodiment of FIG. 9A;

FIG. 10A is a circuit illustration as a superimposed image of anembedded magnetic device in accordance with another embodiment;

FIG. 10B is a center-tapped inductor schematic representative of thefunctionality of the embodiment of FIG. 10A;

FIG. 11 is a flow diagram of an embodiment of a process for producing amagnetic device;

FIG. 12 is an exploded perspective view of an embodiment of an embeddedmagnetic device;

FIGS. 13A-D are top perspective, top, bottom perspective, and bottomviews, respectively, of the base substrate of the embodiment of FIG. 12;

FIGS. 14A and 14B are close-up detailed perspective views of the windingcup periphery surface portion and the hub periphery surface portion,respectively, in accordance with the embodiment of FIG. 13A;

FIGS. 14C and 14D are close-up detailed perspective views of the windingcup periphery surface portion and the hub periphery surface portion,respectively, in accordance with the embodiment of FIG. 12;

FIGS. 15A and 15B are perspective and cross-sectional views,respectively, of a milling tool in accordance with an embodiment;

FIG. 16 is a cross-sectional view of an abrasive tool and work piece, inaccordance with an embodiment;

FIG. 17 is a top perspective view of an assembly comprising the basesubstrate and a core disposed within the winding cup of the embodimentof FIG. 12;

FIG. 18 is a top perspective view of a magnetic device comprising thebase substrate and the second substrate, in accordance with anembodiment;

FIG. 19 is a top perspective view of a magnetic device of the embodimentof FIG. 12, comprising the base substrate, the second substrate, and thetop substrate;

FIG. 20 is a top view of the second conductive trace second end of thesecond conductive pattern as a detailed view in FIG. 18, in accordancewith an embodiment;

FIG. 21 is a top view of the second conductive trace second end of thesecond conductive pattern as a detailed view shown in FIG. 18, inaccordance with an embodiment;

FIG. 22 is a flow diagram of an embodiment of a method of making amagnetic device, in this embodiment, an inductive device;

FIG. 23 is a top perspective view of a circular toroidal core comprisinga bore, core inner sidewall and core outer sidewall that arecomplementary to the feature wall surface of the embodiment of FIG. 1B,in accordance with an embodiment;

FIG. 24 is a top perspective view of an oval-shaped core with an ovalbore, a core inner sidewall and a core outer sidewall that are tapered,in accordance with an embodiment;

FIG. 25 is a top perspective view of a plurality of circular toroidalcores and oval-shaped cores disposed within respective feature andoval-shaped features, respectively, of a base substrate, in accordancewith an embodiment;

FIG. 26 is a top perspective view of a core that has an oval shape andincludes two bores, referred to as a binocular core, in accordance withan embodiment;

FIG. 27 is a top perspective view of a core that has a rectangular shapeand includes one square bore, in accordance with an embodiment;

FIG. 28 is a top perspective view of a core that has a rectangular shapeand includes two square bores, in accordance with an embodiment;

FIG. 29 is a perspective exploded view of a plated through hole (PTH)construction of an embedded magnetic device in accordance with anembodiment;

FIG. 30 is a perspective exploded view of a first magnetic device and asecond magnetic device each in a transformer configuration that arearrayed horizontally in the same assembly sharing the same basesubstrate to define a horizontal multi-device magnetic component, inaccordance with an embodiment;

FIG. 31 is a perspective exploded view of a first magnetic device and asecond magnetic device each in a transformer configuration that arearrayed vertically in the same assembly along the same axis to define avertical multi-device magnetic component, in accordance with anembodiment;

FIG. 32 depicts a schematic diagram of a magnetic component including afirst transformer and a second transformer that are vertically arrayed,in accordance with an embodiment;

FIG. 33A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the first magnetic device, such as shown for first magneticdevice of FIG. 31;

FIG. 33B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the second magnetic device, such as shown for second magneticdevice of FIG. 31;

FIG. 33C illustrates printed circuit board artwork of a third layerfirst secondary winding superimposed on a fourth layer first secondarywinding of the first embedded magnetic device, such as shown for firstmagnetic device of FIG. 31;

FIG. 33D illustrates printed circuit board artwork of a third layersecond secondary winding superimposed on a fourth layer second secondarywinding of the second embedded magnetic device, such as shown for secondmagnetic device;

FIG. 34 depicts a schematic diagram of a magnetic component, in the formof a power transformer, including a first transformer and a secondtransformer that are horizontally arrayed, in accordance with anembodiment;

FIGS. 35A-35B depicts printed circuit board artwork for a magneticcomponent substantially similar to the horizontal multi-transformerembedded magnetic component of FIG. 30 comprising two embedded magnetictransformers in the form of a first magnetic device and a secondmagnetic device, which are connected in a series and parallelconfiguration, in accordance with the schematic of FIG. 34;

FIG. 36 is a schematic diagram of a magnetic component that is usefulfor power converter applications, in accordance with an embodiment;

FIG. 37A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the first magnetic device, such as shown for first magneticdevice of FIG. 31, for a stacked configuration of the schematic of FIG.36;

FIG. 37B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the second magnetic device, such as shown for second magneticdevice of FIG. 31;

FIG. 37C illustrates printed circuit board artwork of a third layerfirst secondary winding superimposed on a fourth layer first secondarywinding of the first embedded magnetic device, such as shown for firstmagnetic device of FIG. 31;

FIG. 37D illustrates printed circuit board artwork of a third layersecond secondary winding superimposed on a fourth layer second secondarywinding of the second embedded magnetic device, such as shown for secondmagnetic device;

FIG. 38 depicts a schematic diagram of a transformer-choke magneticcomponent 1000, in the form of a series connection of a transformerembedded magnetic device and a common mode inductor, in accordance withan embodiment;

FIG. 39A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the transformer embedded magnetic device, such as shown forfirst magnetic device 601 a of FIG. 31, in accordance with the schematicof FIG. 38, in accordance with an embodiment;

FIG. 39B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the common mode inductor, in accordance with an embodiment;

FIG. 40 depicts a schematic diagram of a two-choke magnetic component,in the form of a series connection of a first common mode inductor and asecond common mode inductor, in accordance with an embodiment;

FIG. 41A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the first common mode inductor, in accordance with theschematic of FIG. 40, in accordance with an embodiment;

FIG. 41B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the common mode inductor, in accordance with an embodiment;

FIG. 42 depicts a schematic diagram of a 2-wire common mode inductor inseries with a 2-wire differential mode inductor, in accordance with anembodiment;

FIG. 43A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the 2-wire common mode inductor, in accordance with theschematic of FIG. 42, in accordance with an embodiment;

FIG. 43B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the 2-wire differential mode inductor, in accordance with anembodiment;

FIG. 44 is a cross sectional view of two stacked magnetic components,first embedded magnetic component and second embedded magneticcomponent, with a ground shielding layer there between, in accordancewith an embodiment;

FIG. 45 depicts a section of the circuit artwork for the first fifthsubstrate conductive pattern showing the individual fifth conductivetraces implemented on the first fifth substrate, as shown in FIG. 31, byway of example;

FIG. 46 is a cross sectional view of two stacked magnetic components,first embedded magnetic component and second embedded magneticcomponent, with a ground shielding layer there between, in accordancewith an embodiment;

FIG. 47 depicts a section of the circuit artwork for the first fifthsubstrate conductive pattern showing the individual fifth conductivetraces implemented on the first fifth substrate, as shown in FIG. 31;

FIG. 48a is a schematic diagram of a transformer with a primary andsecondary winding;

FIG. 48b is an EM transformer that is bifilar wound around a toroidshaped core with 2 conductive layers;

FIG. 48c is an EM transformer that is sector wound around a toroidshaped core with 2 conductive layers;

FIG. 49 is a cross section view of an EM transformer that has 2conductive layers and a high voltage cover-lay material on the top andbottom surfaces;

FIG. 50a is a schematic diagram of a transformer with a primary andsecondary winding;

FIG. 50b is an EM transformer with 4 conductive layers, showing justlayers 2 and 3, which are the primary windings;

FIG. 50c is an EM transformer with 4 conductive layers, showing justlayers 1 and 4, which form the secondary windings;

FIG. 50d is an EM transformer with 4 conductive layers;

FIG. 51 is a cross section view of an EM Transformer that has 4conductive layers and a high voltage laminate material separating theprimary and secondary winding layers;

FIG. 52a is a schematic diagram of a transformer with a primary andsecondary winding;

FIG. 52b is an EM transformer that is sector wound with 2 conductivelayers and a square binocular shaped core;

FIG. 52c is an EM transformer that is bifilar wound with 2 conductivelayers and a square binocular shaped core;

FIG. 53a is an EM transformer that has 4 conductive layers and a squarebinocular shaped core, showing layers 1 and 4, which form the primarywinding;

FIG. 53b is an EM transformer that has 4 conductive layers and a squarebinocular shaped core, showing layers 2 and 3, which form the secondarywinding;

FIG. 53c is an EM transformer that has 4 conductive layers and a squarebinocular shaped core;

FIG. 54 is a cross section view of an EM transformer with high voltagelaminate between the primary and secondary windings;

FIG. 55a is a schematic diagram of a transformer with a primary andsecondary winding;

FIG. 55b is an exploded view of a planar magnetic transformer;

FIG. 55c is an EM transformer that has 4 conductive layers, separatelyshowing the windings of each layer; and

FIG. 56 is a cross section view of a 4 layer PM transformer and a highvoltage laminate applied between the primary and secondary windings

DETAILED DESCRIPTION

In the following description, embodiments are disclosed for an apparatusand method for arrayed embedded magnetic components that includemagnetic devices that have a core that is embedded between two or moresubstrates and a winding pattern surrounding the core that isimplemented on and through the two or more substrates. For purposes ofexplanation, specific numbers, materials, and/or configurations are setforth in order to provide a thorough understanding of the embodiments.However, it will also be apparent to those skilled in the art that theembodiments may be practiced without one or more of the specificdetails, or with other processes, materials, components, etc. In otherinstances, well-known structures, materials, and/or operations are notshown and/or described in detail to avoid obscuring the embodiments.Accordingly, in some instances, features are omitted and/or simplifiedin order to not obscure the disclosed embodiments. Furthermore, it isunderstood that the embodiments shown in the figures are illustrativerepresentations and are not necessarily drawn to scale.

References throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, material, and/orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases “in oneembodiment” and/or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, materials, and/orcharacteristics may be combined in any suitable manner in one or moreembodiments.

For the purposes of the subject matter disclosed herein, the term“substrate” refers to an element from which the embodiments of magneticdevices and components are made. A substrate has generally a rectangularshape having a thickness that is substantially less than the width andlength. Substrates may comprise a wide range of materials such as, butnot limited to, plastic material, including, but not limited to polymerand fiberglass, semiconductor material, and so forth. Accordingly, itshould appreciated by those skilled in the art that the substratematerial may be chosen based at least in part on its application.However, for the purposes of describing the subject matter, referencesmay be made to a particular substrate material along with some examples,but the subject matter is not limited to the examples provided. It isunderstood that the substrate provides a means to electrically insulatethe conductive pattern, and therefore, a substrate comprising insulativematerial is known to be used in the art for electronic components. It isunderstood that an insulative layer may be used between the conductivepattern and the substrate wherein the underlying substrate may includean electrically conductive material. In embodiments presented herein, itis provided that the substrate is relatively electrically insulative forpurposes of illustrating the subject matter, yet may include conductivetraces, ferromagnetic elements, and other electrically conductivematerials.

For the purposes of the subject matter disclosed herein, reference tothe terms “conductive pattern”, “conductive trace”, “circuit pattern”and “circuit trace”, used interchangeably herein, refer to anelectrically conductive material that defines at least a portion of anelectric circuit pattern or winding pattern. Electric circuit patternsare well known, for example, in the printed circuit board arts.

For the purposes of the subject matter disclosed herein, reference tothe terms “windings”, “winding-type electric circuits”, and “windingpatterns”, used interchangeably herein, refer to an electricallyconductive material that defines an electric circuit patternsubstantially analogous in function to a circuit comprising a wire thatis wrapped around a mandrel. A winding pattern may comprise one or moreconductive patterns and conductive traces that are electricallyinterconnected.

For the purposes of the subject matter disclosed herein, reference tothe term “permeability material” refers to a material making up a coreof a magnetic component. Cores are known in the art. For example, butnot limited thereto, permeability material includes air, a hollow devicemade from non-ferromagnetic material having a permeability approaching1, and ferromagnetic material. A core may comprise a permeabilitymaterial that is a solid, semisolid, or gas.

Additionally, for the purposes of describing various embodiments,references may be made to “magnetic devices” and “magnetic components”.However, it should be appreciated by those skilled in the relevant artthat magnetic components may include magnetic devices having one or moreof a wide variety of magnetic functionality such as, but not limited to,transformer devices, inductor devices, filter devices, and so forth, andaccordingly, the claimed subject matter is not limited in scope in theserespects.

For the purposes of the subject matter disclosed herein, reference to a“magnetic device” refers to a core surrounded by one or more conductivepatterns operable to facilitate magnetic properties of the core when theone or more conductive patterns are electrically energized. Reference to“magnetic component” refers to two or more magnetic devices that areelectrically interconnected. Further, embodiments of methods of makingmagnetic devices and magnetic components are presented herein.

For the purposes of the subject matter disclosed herein, reference to an“array” refers to a spatial relationship between two or more magneticdevices. Examples of particular spatial relationships include, but notlimited to, side-by-side in a horizontal integration, also referred toas a horizontal array, and top-to-bottom or coaxial alignment in avertical integration, also referred to as a vertical array, andcombinations thereof.

For the purposes of the subject matter disclosed herein, reference to“embedded device” or “embedded component” refers to a magnetic device ormagnetic component where the core is contained within or enclosed by oneor more substrates.

For the purposes of the subject matter disclosed herein, “inductor” maybe used in a broad sense to refer to an individual inductor device, twoor more inductors electrically connected in a differential modeconfiguration, and two or more inductors electrically connected in acommon mode choke configuration, among other configurations.

Embodiments of a magnetic device comprise a wound component, implementedby embedding a core defining a toroidal shape into a substrate anddisposing conductive windings defining a complementary toroidal shapearound the core. A toroidal shape refers to a ring or donut shape.Windings may be implemented, by way of example but not limited to,printed circuit layers, plated vias, and combinations thereof.Embodiments of methods of making magnetic devices provide a means forproducing inductors, transformers and other wound electrical andmagnetic devices with an automated batch process. Some of the benefitsinclude one or more of low cost construction, high frequencyperformance, consistent performance, and a low profile form. Inaccordance with an embodiment, the magnetic device is a printed circuitboard (PCB) upon which other passive and active components may beplaced. In accordance with other embodiments, other magnetic devices maybe vertically integrated with a magnetic device which may reduce thesize of the system implementation.

Embodiments of a magnetic device comprise a wound component, implementedby embedding a core defining a binocular shape into a substrate anddisposing conductive windings defining a complementary binocular shapearound the core. A binocular shape refers to a rectangle or oval withtwo apertures or windows.

Embodiments of a magnetic device comprise conductive windings disposedaround a core. The windings may be disposed using printed circuittechniques, in accordance with embodiments. For high volume production,specific design rules are followed regarding the conductor widths,spacings, and the aspect ratio (length/diameter) of plated vias that maybe used to interconnect winding layers. There are limits to the numberof windings that can be applied to a given structure of the core. Theprinted circuit fabrication equipment imposes limitations on thesubstrate thickness, which constrains the height of the core. Thethickness and volume of the core determines, at least in part, the powercapability of the magnetic device.

Higher power applications require a larger volume of permeabilitymaterial to transfer electromagnetic energy between the windings of themagnetic device. For high power applications, circuit plating thicknesscan limit the amount of current that the magnetic device can deliver. Toovercome these limits and provide higher inductance and powercapability, methods and apparatus are provided that provide multiplemagnetic devices arranged and interconnected in an array.

Inductance may be increased when windings are connected in series. Whenconnected in parallel, the inductance is reduced. Winding resistance andAC impedance is also reduced when inductors are connected in parallel,which is, for example, beneficial for power applications. In powerapplications, heat is generated within the windings and the corematerial, by way of example. Spreading the heat between multiplewindings and cores is beneficial for dissipating heat and managing thetemperature of the circuit. Also, loss parameters such as, but notlimited to, leakage inductance and core loss are proportional to thenumber of windings on the core, the core size and volume. In powerapplications, these parameters impact the system efficiency and energyloss. In accordance with embodiments, system efficiency and energy lossmay be reduced by implementing the inductor or transformer device usingmultiple smaller cores, rather than one large core.

FIG. 1A is a perspective exploded view and FIG. 1B is a cross-sectionalexploded view about line 1B-1B of an embedded magnetic device 100 inaccordance with an embodiment. The embedded magnetic device 100comprises a base substrate 102, a first conductive pattern 108, core110, a second substrate 112, a second conductive pattern 116, and meansfor electrically coupling the first conductive pattern 108 and secondconductive pattern 116, such as, but not limited to various types ofvias or interconnects 140 and electrically conductive traces.

The base substrate 102 defines a base substrate first surface 104 and abase substrate second surface 105 opposite the base substrate firstsurface 104, and a feature 106. The first conductive pattern 108 isdisposed on and about the feature 106. The core 110 is disposed withinthe feature 106. The second substrate 112 comprises a second substratefirst surface 115 and a second substrate second surface 114. The secondsubstrate first surface 115 is disposed on and coupled to the basesubstrate first surface 104, over the feature 106, and over the core110. The second conductive pattern 116 is disposed on the secondsubstrate second surface 114 in complementary alignment with the firstconductive pattern 108. The first conductive pattern 108 and the secondconductive pattern 116 comprise an electrically conductive material. Aswill be further described below, the first conductive pattern 108 andthe second conductive pattern 116 are electrically interconnected so asto electrically cooperate to be operable for facilitating magneticproperties of the core 110 when electrically energized, in accordancewith various embodiments.

It should be appreciated that FIGS. 1A and 1B illustrate an explodedview to describe an embodiment of the claimed subject matter, andaccordingly, as will be described in further detail, the embeddedmagnetic device 100 may have core 110 substantially enclosed within thefeature 106, with the second substrate 112 substantially covering thecore 110. The electrically interconnected first conductive pattern 106and second conductive pattern 116 surround the core 110, thereby forminga winding pattern, that is, a winding-type relationship such asassociated with a winding-type electric circuit that cooperates inelectrical communication when coupled to a time varying voltagepotential. Such winding-type relationship is similar in function toknown electrical devices in the art that comprise a wire-wrapped coreconfiguration.

Continuing to refer to FIGS. 1A and 1B, the base substrate 102 is shownhaving a substantially rectangular shape. However, it should beappreciated that the base substrate 102 may have any shape such as, butnot limited to, substantially circular, substantially oval,substantially square, or any other polygonal shape.

Additionally, the base substrate 102 may comprise many types of materialsuitable for use as a substrate, such as, but not limited to, materialsuitable for printed circuit boards (PCBs), various plastic materials,material suitable for injection molding, ceramic materials, and soforth.

For example, in an embodiment, the base substrate 102 may comprise athermoplastic material, such as, but not limited to, polyimide resin andpolyetherimide (PEI) material. In another embodiment, the base substrate102 may comprise a plastic resin material that may be suitable forinjection molding or compression molding, such as, but not limited to,liquid crystal polymer material. It should be appreciated by thoseskilled in the relevant art that the shape and materials described aremerely examples, and the claimed subject matter is not limited in scopein these respects.

In the embodiment of FIGS. 1A and 1B, the feature 106 extends below aplane defined by the base substrate first surface 104. The feature 106defines a toroidal shape depression, also referred herein as a groove ofrevolution about an axis 107, depending from the base substrate firstsurface 104 into the base substrate 102. The axis 107 is perpendicularto a plane defined by the base substrate first surface 104. The feature106 defines a hub 120 having a hub top surface 124 that extends to theplane defined by the base substrate first surface 104. The feature 106further defines a bottom wall 139 and a feature inner wall 119 and afeature outer wall 129 contiguous with the bottom wall 139 defining afeature wall surface 109. It is appreciated that in other embodiments,the feature inner wall 119 and feature outer wall 129 may be contiguouswith no bottom wall 139 as dictated by design preference.

It should be appreciated by those skilled in the relevant art that thefeature 106 may define a wide range of shapes such as, but not limitedto, a rod, oval, oblong, and so forth, and accordingly, the claimedsubject matter is not limited in scope in these respects. Some of theseother feature shapes are presented below by way of example, and notlimited thereto.

A variety of processes may be utilized in order to facilitate formationof the feature 106 in the base substrate 102. For example, in anembodiment, the feature 106 is formed by utilizing a lithographyprocess, such as, but not limited to photolithography. Photolithographyis well known in the art in which selected regions of a material areremoved so as to reveal underlying elements or produce three-dimensionalstructures in a substrate.

In other embodiments, the feature 106 may be formed by utilizing amachining process such as, but not limited to, a micromachining process,wherein material is selectively removed with a mechanical process.Various processes may be utilized to facilitate formation of a feature,and accordingly, the claimed subject matter is not limited to aparticular process.

As shown in FIGS. 1A and 1B, the feature 106 defines a feature peripherysurface portion 122 on the base substrate first surface 104. The hub topsurface 124 defines a hub periphery surface portion 126. The featureperiphery surface portion 122 and the hub periphery surface portion 126are those portions where a portion of the first conductive pattern 108is disposed on the respective surfaces. The first conductive pattern 108is disposed on a portion of the feature 106 and on a portion of thefeature periphery surface portion 122 and the hub periphery surfaceportion 126. In the illustrated embodiment, the first conductive pattern108 is disposed in a manner whereby the first conductive pattern 108covers portions of the feature wall surface 109, the feature peripherysurface portion 122 and the hub periphery surface portion 126.

A variety of methods may be utilized in order to dispose the firstconductive pattern 108 on the respective surfaces. In an embodiment, thefirst conductive pattern 108 is disposed on the respective surfaces byutilizing a stamping process, such as, but not limited to, stamping aconductive pattern from sheet material, forming the conductive patternto conform to the shape characteristics of the feature 106, and couplingthe conductive pattern to the feature 106 such as, but not limited to,using adhesive or a molding process.

In another embodiment, the first conductive pattern 108 is disposed onthe respective surfaces by utilizing a plating process, such as, but notlimited to, chemical and/or electro-plating a conductive pattern on asubstrate. In another embodiment, the first conductive pattern 108 isdisposed on the respective surfaces by utilizing a lithography process,such as, but not limited to, photolithography. The photolithographyprocess may be used to first plate or cover the substrate withconductive material, dispose a photo-resist onto the conductive materialand use photolithography and chemical etching or laser ablation and thelike to produce the circuit pattern from the conductive material. In yetanother embodiment, a structuring process, such as, but not limited to,laser structuring process may be utilized to dispose the firstconductive pattern 108 on the respective surfaces, such as wherein alaser is used to prepare the surface for plating with a conductivematerial. Various other processes may be utilized to dispose aconductive pattern on the respective surfaces, and accordingly, theclaimed subject matter is not limited to a particular process.

Referring again to FIGS. 1A and 1B, the feature inner wall 119 andfeature outer wall 129 taper inward towards each other as they extendtowards the bottom wall 139. Among other things, the taper of thefeature inner wall 119 and feature outer wall 129 ensures that thefeature inner wall 119 and feature outer wall 129 are viewable by thoseconductive material deposition processes that require line-of-sightsurface exposure.

For example, but not limited thereto, imaging techniques may be utilizedto dispose the conductive pattern on the respective surfaces. An exampleof an imaging technique known in the art includes, but is not limitedto, photolithography, which is a method for disposing two-dimensionalcircuit traces on a printed circuit board, for example. In conventionalphotolithography of a planar substrate, the surface to be treated mustbe viewable by an imaging device that projects imaging onto thesubstrate surface. Likewise, imaging techniques used to dispose theconductive pattern on the feature inner wall 119 and feature outer wall129 requires the same to be viewable by the imaging device. Tofacilitate such imaging, in accordance with an embodiment as shown inFIGS. 1A and 1B, the feature inner wall 119 and feature outer wall 129depend into the base substrate first surface 104 at an obtuse angledefining an inward-sloping configuration of the feature inner wall 119and feature outer wall 129 which presents an imaging device a broaderviewable area as compared with a more vertical orientation of thefeature inner wall 119 and feature outer wall 129.

The first conductive pattern 108 and second conductive pattern 116 maycomprise a wide variety of electrically conductive materials such as,but not limited to, copper, tin, aluminum, gold, silver, and othervarious types of conductive tracing materials. Accordingly, the claimedsubject matter is not limited in scope in these respects.

In accordance with an embodiment, after the first conductive pattern 108is disposed on the feature 106, the portion of the first conductivepattern 108 on the feature wall surface 109 may be covered with anelectrically insulative layer, such as, but not limited to, encapsulatematerial. The electrically insulative layer is operable, among otherthings, to prevent electrical shorting between the core 110 and thefirst conductive pattern 108.

Continuing to refer to FIGS. 1A and 1B, the core 110 is shown as havinga shape defined at least in part by the shape of the feature 106. Thatis, in the embodiment of FIGS. 1A and 1B, the core 110 comprises asubstantially toroidal shape about the axis 107 that substantially fitswithin and corresponds to the toroidal shape of the feature 106. In theembodiment of FIGS. 1A and 1B, the core 110 is shown as a separate solidobject, where the solid object may be placed within the feature 106 byvarious methods such as, but not limited to, utilizing a pick and placemachine. However, in another embodiment, the core 110 may be of a liquidform whereby the liquid may be poured into the feature 106 andsubsequently cured to a solid mass. In another embodiment, the core 110may be in the form of a powder whereby the powder may be disposed intothe feature 106. In yet another embodiment, the core 110 may comprise ofmaterial that may be utilized with a vibration-based process tofacilitate placement of the core substantially within the feature 106.That is, a method by which a vibration machine may be utilized to settleor align the core 110 within the feature 106. Accordingly, the claimedsubject matter is not limited in scope in these respects.

The core 110 may comprise a wide variety of permeability materials suchas, but not limited to, ferromagnetic materials that may include ferritematerials, iron materials, metal materials, metal alloy materials, andso forth. Additionally, the core 110 may comprise permeability materialsbased at least in part on the particular utilization of a magneticdevice. For example, a magnetic device to be utilized as an isolationtransformer may include a core having a high relative permeability. Inanother example, a magnetic device to be utilized as a common modefilter may include a core having a moderate relative permeability.Further, as previously alluded to, the size and shape of the core 110may be based at least in part on the utilization of the magnetic device.It is understood that other design parameters may be considered in thematerial type and method of forming the core 110, such as, but notlimited to, the coefficient of thermal expansion mismatch with thesubstrate that may be a factor in device production and use. Also, it isunderstood that an air core, that is, a core 110 having a relativepermeability of 1, such as implemented by a solid or hollow core that isnon-ferromagnetic as well as an empty feature, may be used in certainembodiments. Accordingly, the claimed subject matter is not limited inscope in these respects.

FIG. 1C is a cross-sectional view about cut line 1C-1C of the magneticdevice 100 of the embodiment of FIG. 1A. In accordance with embodiments,wherein the core 110 is a solid element, after the core 110 is disposedwithin the feature 106, a gap 142 may be defined between the core 110and the feature 106. This gap 142 may be filled with an encapsulatematerial that is gap filling; that is, a material that is able to fillthe gap 142. The encapsulate material may be operable for, among otherthings, adhering the core 110 within the feature 106 and to preventshifting therein, and electrically insulating the core 110 from thefirst conductive pattern 108.

In FIGS. 1A-1C, for the purposes of describing the embodiment, thesecond substrate 112 may be shown as a relatively thin layer as comparedto the base substrate 102. However, the second substrate 112 may berepresentative of one or more layers, such as, but not limited to,printed circuit layers disposed on the base substrate first surface 104of the base substrate 102 and does not necessarily denote a single pieceof substrate, but it also could be a single piece of substrate. Thesecond substrate 112 may also be in a form of a sheet. Additionally, thesecond substrate 112 does not necessarily need to comprise the samematerial as the base substrate 102 and may comprise a differentmaterial. For example, in one embodiment, the second substrate 112 mayinclude various lamination layers that facilitate buildup of circuitlayers. In another embodiment, a liquid material may be disposed on thebase substrate 102 such as, but not limited to, a liquid dielectricmaterial that is subsequently cured to at least a substantially rigidform. For example, a liquid dielectric material, such as a polyimideepoxy, may be disposed by utilizing at least one of a spray, roller,and/or a squeegee process. A subsequent conductive foil layer may belaminated to the liquid dielectric material. It should be appreciated bythose skilled in the relevant art that the second substrate 112 may bedisposed on and coupled to the base substrate first surface 104 of thebase substrate 102 by a wide variety of processes. Accordingly, theclaimed subject matter is not limited to any one particular process.

In the embodiment illustrated in FIGS. 1A-1C, the second conductivepattern 116 is shown on the second substrate second surface 114 of thesecond substrate 112. As previously described, the second conductivepattern 116 may be disposed on the second substrate 112 utilizing avariety of processes, such as, but not limited to, a lamination process,lithography process, etching process, a screen printing process, a laserstructuring process, and so forth. That is, the second conductivepattern 116 may be disposed as part of the process of providing thesecond substrate 112, and accordingly, the claimed subject matter is notlimited in these respects.

In an embodiment, the second conductive pattern 116 is disposed byutilizing a stamping process, such as, but not limited to, stamping aconductive pattern from sheet material and coupling the conductivepattern to the second substrate 112, such as, but not limited to, usingadhesive or embedding or over-molding the conductive pattern into thesecond substrate second surface 114 during a molding process.

In the embodiment of FIGS. 1A-1C, the second conductive pattern 116comprises a pattern that is complimentary to the first conductivepattern 108 so as to cooperate electrically to facilitate electrical“wrapping” of the core 110 between the first conductive pattern 108 andthe second conductive pattern 116. Additionally, the first conductivepattern 108 and the second conductive pattern 116 are electricallyinterconnected, such as by one or more vias and/or interconnects 140, aswill be described in detail. Further, the first conductive pattern 108and the second conductive pattern 116 are electrically coupled togetherto define one or more electrical circuits each having a positiveterminal W1A, W2A and a negative terminal W1B, W2B, corresponding to thetwo electrical circuit embodiment of FIGS. 6A and 6B, suitable forcoupling to a voltage source and/or other external components.

Together, the first conductive pattern 108 and the second conductivepattern 116 electrically cooperate to be capable of facilitatingmagnetic properties of the core 110 when coupled to a time varyingvoltage potential and/or other external components. For example, thefirst conductive pattern 108 and the second conductive pattern 116cooperate to be capable of inducing a magnetic field upon the core 110when the first conductive pattern 108 and second conductive pattern 116are electrically coupled to a time varying voltage potential.

FIGS. 2A and 2B are top and cross-sectional views about line 2B-2B,respectively, of the base substrate 102 in accordance with theembodiment of FIGS. 1A and 1B. In FIG. 2A, the base substrate 102comprises the base substrate first surface 104 and the feature 106. Asshown in FIG. 2B, the feature 106 depends from the base substrate firstsurface 104 into the base substrate 102. In this embodiment, the feature106 defines a substantially toroidal shape formed as a depression intothe base substrate 102 and defining the hub 120.

FIG. 3 is a top view of the base substrate 102 and the first conductivepattern 108 in accordance with the embodiment of FIGS. 1A and 1B. Thebase substrate 102 comprises the base substrate first surface 104 andthe feature 106. The first conductive pattern 108 is disposed within thefeature 106 and on the feature periphery surface portion 122 and on thehub periphery surface portion 126. The first conductive pattern 108comprises a plurality of first conductive traces 128 that arediscontinuous and radiate from about an axis 107. The use of the term“discontinuous” in describing traces, such as conductive traces 128,means that the traces are not electrically interconnected at this pointof the construct.

The first conductive traces 128 are disposed from the hub peripherysurface portion 126 to the feature periphery surface portion 122 alongthe feature wall surface 109 there between, also as shown in FIGS. 2Aand 2B. Each of the first conductive traces 128 comprise a trace hub end127 that is associated with the hub periphery surface portion 126 and atrace feature end 125 that is associated with the feature peripherysurface portion 122.

Referring again to FIG. 1A, the second conductive pattern 116 comprisesa plurality of second conductive traces 138 that are discontinuous andradiate from about the axis 107. Second conductive traces 138 comprise asecond conductive trace first end 135 positioned closest to the axis 107and a second conductive trace second trace end 137, opposite the secondconductive trace first end 135. The number of second conductive traces138 is determined by the number of first conductive traces 128 and for aparticular purpose. In accordance with embodiments, including that shownin FIG. 1A, the number of second conductive traces 138 are equal to thenumber of first conductive traces 128. In the embodiment of FIG. 1A, thefirst conductive traces 128 and the second conductive traces 138 definea complimentary pattern such that the second conductive traces 138radiate from about the axis 107 such that a second conductive tracefirst end 135 is aligned above a trace hub end 127 of a first conductivetrace 128, and a second conductive trace second trace end 137 is alignedabove a trace feature end 125 of an adjacent first conductive trace 128when the second conductive pattern 116 and the second substrate 112 arecoupled to the base substrate 102.

Interconnects 140, as shown in FIG. 1B, are located between therespective second conductive trace first end 135 and the trace hub end127 and the second conductive trace second trace end 137 and the tracefeature end 125 affecting an electrical coupling there between.Interconnects 140 may also be referred to as vias, which are known inthe art. The interconnection of the first conductive pattern 108 and thesecond conductive pattern 116 define a winding-type electric circuitaround the core 110. In accordance with an embodiment, the magneticdevice 100 provides wherein the first conductive pattern 108 and secondconductive pattern 116 are electrically coupled so as to define at leastone continuous winding beginning at a first electrical tap W1 andterminating at a second electrical tap W2, such as shown in FIG. 1A,which are operable to be coupled to a time varying voltage potential.

FIG. 4 illustrates a perspective exploded view of an embedded magneticdevice 200 in accordance with another embodiment. In FIG. 4, similar tothe embedded magnetic device 100, shown in FIGS. 1A and 1B, the embeddedmagnetic device 200 includes a base substrate 102, a base substratefirst surface 104 defining a feature 106 which defines in part a cavity231, a first conductive pattern 108 on the base substrate first surface104 and the feature 106, a second substrate 212 including a secondsubstrate second surface 214, a second substrate first surface 215opposite the a second substrate second surface 214, and a secondconductive pattern 216 on the second substrate second surface 214.However, in this embodiment, the core 110 is relatively large based atleast in part on its application. Accordingly, a second feature 206which defines in part the cavity 231 depends from the second substratesecond surface 214 to facilitate accommodation of a portion of the core110 that extends above the base substrate first surface 104 whendisposed in the cavity 231.

The second feature 206 defines a second groove of revolution 222 aboutan axis 107 perpendicular to the second substrate second surface 214,shown in FIG. 4 in relief as the second substrate 212 is shown as anexample of a relatively thin structure. The second feature 206 defines adepression (not shown) in the surface of the second substrate 212opposite the second substrate second surface 214. The second groove ofrevolution 222 defines a second feature outer surface 219 surrounding asecond groove hub (mostly hidden from view) including a second grooveperiphery 221 of the second substrate second surface 214. The secondsubstrate 212 further includes the second conductive pattern 216disposed on the second feature 206. The base substrate 102 and secondsubstrate 212 are placed in cooperative engagement so as to define thecavity 231 defined by the feature 106 defining a groove of revolutionand the second groove of revolution 222.

As shown, the second conductive pattern 216 is disposed to at leastpartially cover a second feature outer surface 219 of the second feature206 and about a second groove periphery 221 of the second substratesecond surface 214 so as to substantially correspond to complementaryelements on the base substrate 102. As previously described, the secondconductive pattern 216 and the first conductive pattern 108 areelectrically interconnected suitable for a particular purposesubstantially as described above.

Embodiments of embedded magnetic devices are provided below by way ofexample only, and the embodiments in accordance with the disclosedsubject matter are not limited thereto. By way of example, but notlimited thereto, in the embodiment of FIG. 4, the second conductivepattern 216 may be disposed on the surface of the second substrate 212that is opposite the second substrate second surface 214 and within thedepression (not shown) discussed above.

FIG. 5A is a circuit illustration as a superimposed image of anembodiment of an embedded magnetic device 100 a including a basesubstrate (not shown) having a feature 106, a first conductive pattern108 a, core 110, a second substrate (not shown), and a second conductivepattern 116 a. The first conductive pattern 108 a and the secondconductive pattern 116 a are electrically interconnected so as to definefour interleaved electrical paths capable of facilitating a dual commonmode filter functionality. FIG. 5B is a dual common mode filterschematic 103 a representative of the functionality of the embodiment ofFIG. 5A. It should be appreciated that the substrate is not shown andthe core is shown as clear so as to not obstruct in order to betterillustrate the embodiment, and in particular, the interrelationshipbetween the first conductive pattern 108 a and the second conductivepattern 116 a.

The first conductive pattern 108 a and second conductive pattern 116 adefine four circuits. A first circuit terminates at electrical taps W1Aand W1B suitable for coupling with a voltage source. A second circuitterminates at electrical taps W2A and W2B suitable for coupling with avoltage source. A third circuit terminates at electrical taps W3A andW3B suitable for coupling with a voltage source. A fourth circuitterminates at electrical taps W4A and W4B suitable for coupling with avoltage source. The dots shown in FIG. 5B indicate that, in thisembodiment, both W1A and W1B have the same polarity, that is, the samewinding orientation. The interaction of the first and second circuitswith the core 110 and the interaction of the third and fourth circuitswith the core 110, and in combination, are represented schematically inFIG. 5B.

FIG. 6A is a circuit illustration as a superimposed image of an embeddedmagnetic device 100 b in accordance with another embodiment. In FIG. 6A,the embedded magnetic device 100 b includes a base substrate (not shown)having a feature 106, a first conductive pattern 108 b, a core 110, asecond substrate (not shown), and a second conductive pattern 116 b. Thefirst conductive pattern 108 b and the second conductive pattern 116 bare electrically interconnected so as to define two interleavedelectrical paths capable of facilitating single common mode filterfunctionality. FIG. 6B is a single common mode filter schematic 103 brepresentative of the functionality of the embodiment of FIG. 6A. Itshould be appreciated that the substrate is not shown and the core isshown as clear so as to not obstruct in order to better illustrate theembodiment, and in particular, the interrelationship between the firstconductive pattern 108 b and the second conductive pattern 116 b.

The first conductive pattern 108 b and second conductive pattern 116 bdefine two circuits. A first circuit terminates at electrical taps W1Aand W1B suitable for coupling with a voltage source. A second circuitterminates at electrical taps W2A and W2B suitable for coupling with avoltage source. The interaction of the first and second circuits withthe core 110, and in combination, are represented schematically in FIG.6B.

FIG. 7A is a circuit illustration as a superimposed image of an embeddedmagnetic device 100 c in accordance with another embodiment. In FIG. 7A,the embedded magnetic device 100 c includes a base substrate (not shown)having a feature 106, a first conductive pattern 108 c, a core 110, asecond substrate (not shown), and a second conductive pattern 116 c. Thefirst conductive pattern 108 c and the second conductive pattern 116 care electrically interconnected so as to define one electrical pathcapable of facilitating a single inductor functionality. FIG. 7B is asingle inductor schematic 103 c representative of the functionality ofthe embodiment of FIG. 7A. The first conductive pattern 108 c and thesecond conductive pattern 116 c define one circuit. The circuitterminates at electrical taps W1A and W1B suitable for coupling with avoltage source. It should be appreciated that the substrate is not shownand the core is shown as clear so as to not obstruct in order to betterillustrate the embodiment, and in particular, the interrelationshipbetween the first conductive pattern 108 c and the second conductivepattern 116 c. The interaction of the circuit with the core 110 isrepresented schematically in FIG. 7B.

FIG. 8A is a circuit illustration as a superimposed image of a magneticdevice 100 d in accordance with another embodiment. In FIG. 8A, themagnetic device 100 d includes a base substrate (not shown) having afeature 106, a first conductive pattern 108 d, a core 110, a secondsubstrate (not shown), and a second conductive pattern 116 d. The firstconductive pattern 108 d and the second conductive pattern 116 d areelectrically interconnected so as to define two interleaved electricalpaths capable of facilitating a transformer functionality. FIG. 8B is anisolation transformer schematic 103 d representative of thefunctionality of the embodiment of FIG. 8A. It should be appreciatedthat the substrate is not shown and the core is shown as clear so as tonot obstruct in order to better illustrate the embodiment, and inparticular, the interrelationship between the first conductive pattern108 a and the second conductive pattern 116 d.

The first conductive pattern 108 a and second conductive pattern 116 ddefine two circuits, each having a center electrical tap CT1, CT2. Afirst circuit terminates at electrical taps W1A and W1B suitable forcoupling with a voltage source, with a center electrical tap CT1substantially there between. A second circuit terminates at electricaltaps W2A and W2B suitable for coupling with a voltage source, with acenter electrical tap CT2 substantially there between. The interactionof the first and second circuits with the core 110, and in combination,are represented schematically in FIG. 8B.

FIG. 9A is a circuit illustration as a superimposed image of an embeddedmagnetic device 100 e in accordance with another embodiment. In FIG. 9A,the embedded magnetic device 100 e includes a base substrate (not shown)having a feature 106, a first conductive pattern 108 e, a core 110, asecond substrate (not shown), and a second conductive pattern 116 e. Thefirst conductive pattern 108 e and the second conductive pattern 116 eelectrically cooperate so as to be capable of facilitating magneticproperties of the core 110, and in this particular embodiment, magneticdevice 100 e may be capable of being utilized as three-wire common modechoke (i.e., a three-wire common mode choke functionality). FIG. 9B is athree-wire common mode choke schematic 103 e representative of thefunctionality of the embodiment of FIG. 9A. It should be appreciatedthat the substrate is not shown and the core is shown as clear so as tonot obstruct in order to better illustrate the embodiment, and inparticular, the interrelationship between the first conductive pattern108 e and the second conductive pattern 116 e.

The first conductive pattern 108 e and second conductive pattern 116 edefine three circuits. A first circuit terminates at electrical taps W1Aand W1B suitable for coupling with a voltage source. A second circuitterminates at electrical taps W2A and W2B suitable for coupling with avoltage source. A third circuit terminates at electrical taps W3A andW3B suitable for coupling with a voltage source. The interaction of thefirst, second and third circuits with the core 110, and in combination,are represented schematically in FIG. 9B.

The three-wire common choke is particularly useful for Ethernetapplications. While the embodiment of FIG. 9A illustrates a three-wirechoke, it is appreciated that a similar winding configuration may beutilized to make a 4-wire choke, 5-wire choke, on up to n-wire choke.Multi-winding chokes may be useful in applications for particularpurposes.

FIG. 10A is a circuit illustration as a superimposed image of anembedded magnetic device 100 f in accordance with another embodiment. InFIG. 10A, the embedded magnetic device 100 f includes a base substrate(not shown) having a feature 106, a first conductive pattern 108 f, acore 110, a second substrate (not shown), and a second conductivepattern 116 f The first conductive pattern 108 f and the secondconductive pattern 116 f electrically cooperate so as to be capable offacilitating magnetic properties of the core 110, and in this particularembodiment, magnetic device 100 f may be capable of being utilized as acenter-tapped inductor (i.e., a center-tapped inductor functionality).FIG. 10B is a center-tapped inductor schematic 103 f representative ofthe functionality of the embodiment of FIG. 10A. It should beappreciated that the substrate is not shown and the core is shown asclear so as to not obstruct in order to better illustrate theembodiment, and in particular, the interrelationship between the firstconductive pattern 108 f and the second conductive pattern 116 f.

The first conductive pattern 108 f and second conductive pattern 116 fdefine one circuit having a center electrical tap. The circuitterminates at electrical taps W1A and W1B suitable for coupling with avoltage source, with a center electrical tap CT substantially therebetween. The interaction of the first conductive pattern 108 f, secondconductive pattern 116 f, and the center electrical tap with the core110 is represented schematically in FIG. 10B.

The above embodiments are simply examples of various modes of electricalinterconnection of the first and second conductive patterns and are notlimited thereto. It is appreciated that a similar winding configurationmay be utilized to make an inductor with 2, 3 or N-number of electricaltaps.

In various embodiments, one or more embedded magnetic devices may beformed on a single substrate. Additionally, because the magneticproperties of an embedded magnetic device may be based at least in parton its conductive pattern, its feature size, permeability materialutilized, and/or so forth, more than a single type of embedded magneticdevice may be formed from a single base substrate, and accordingly, theclaimed subject matter is not limited in these respects.

FIG. 11 is a flow diagram of an embodiment of a process 10 for producinga magnetic device. The process 10 comprises providing a base substrateincluding a feature 12. As previously described, the base substrate maycomprise a wide variety of materials that may be utilized for PCBs. Thebase substrate includes the feature formed on the base substrateutilizing a wide variety of processes as previously described. A firstconductive pattern is disposed on and about at least a portion of thefeature and the base substrate 14. A core 110 is disposed within thefeature 16. A second substrate is disposed over the core and the basesubstrate 18. A second conductive pattern is disposed on the secondsubstrate 19 and electrically coupled to the first conductive pattern,thereby facilitating a one or more winding electric circuits of theconductive patterns around the core 20.

In accordance with another embodiment of the process 10, after theconductive pattern is disposed over the feature and the base substrate14, the conductive pattern is covered with an electrically insulativelayer 15. The electrically insulative layer is operable, among otherthings, to prevent electrical shorting between the core and the firstconductive pattern.

In accordance with another embodiment of the process 10, after the coreis disposed within the feature 16, a gap defined between the core andthe feature is filled with an encapsulate material that is electricallyinsulative 17. The encapsulate material may be operable for, among otherthings, coupling the core within the feature and to prevent shiftingthereof.

In some of the above embodiments the feature has tapered sidewalls so asto allow for line-of-sight-dependent conductive material depositionprocesses. Further embodiments are presented below wherein magneticdevices need not have features having tapered sidewalls.

FIG. 12 is an exploded perspective view of an embodiment of an embeddedmagnetic device 300. The embedded magnetic device 300 comprises a basesubstrate 302, a first conductive pattern 308, a core 110, a secondsubstrate 312, a second conductive pattern 316, a top substrate 332, atop conductive pattern 376 and a secondary conductive pattern hiddenfrom view. As will be described in detail below, conductive patternsformed on the base substrate 302, the second substrate 312, and topsubstrate 332 define one or more winding electrical circuits surroundingthe core 110 so as to impart magnetic properties to the core 110 whenthe one or more electrical circuits are energized by a voltage source.

The embodiment of FIG. 12 illustrates the modularity of the methods andapparatus of embedded magnetic devices in accordance with embodiments ofthe disclosed subject matter. This modularity provides the flexibilityof producing embedded magnetic devices having predeterminedfunctionality. By way of example, providing the top substrate 332 asshown in FIG. 12, is useful, by way of example but not limited thereto,for providing power transformer functionality to the embedded magneticdevice, where there is defined a primary and secondary winding. By wayof another example, only the base substrate 302 and second substrate 312may be used, by way of example but not limited thereto, for providinginductor functionality to the embedded magnetic device, where only aprimary or single winding is defined.

The second substrate 312 and top substrate 332 are substantially similarto the second substrate 112 of the embodiment of FIG. 1A. Similarly, aspreviously described, the second conductive pattern 316 and topconductive pattern 376 may be disposed on the second substrate 312 andtop substrate 332, respectively, utilizing a variety of processes suchas, but not limited to, a lamination process, lithography process,etching process, a screen printing process, a laser structuring process,molding process, and so forth. That is, the second conductive pattern316 and top conductive pattern 376 may be disposed as part of theprocess of providing the second substrate 312 and top substrate 332,respectively, and accordingly, the claimed subject matter is not limitedin these respects.

The base substrate 302 of the embodiment of FIG. 12 is suitable for anembedded magnetic device having a primary and secondary winding electriccircuit. FIGS. 13A-D are top perspective, top, bottom perspective, andbottom views, respectively, of the base substrate 302 of the embodimentof FIG. 12. The base substrate 302 defines a first base surface 304 anda second base surface 305 opposite the first base surface 304. Dependingfrom the first base surface 304 is a feature defining a winding cup 306.The winding cup 306 may be disposed into the first base surface 304 byany suitable method including, but not limited to, machining and moldingprocesses as previously described.

The winding cup 306 defines a groove of revolution about an axis 107perpendicular to the first base surface 304. The winding cup 306 definesa winding cup surface 309 surrounding a hub 320. The winding cup surface309 defines a winding cup bottom 345, a cup inner wall 319 and a cupouter wall 329 contiguous with the winding cup bottom 345. It isappreciated that in other embodiments, the cup inner wall 319 and cupouter wall 329 may be contiguous with each other and with no winding cupbottom as dictated by design preference. The hub 320 extends from thefirst base surface 304 to the winding cup bottom 345 of the winding cup306. The hub 320 defines a hub top surface 324 that is substantiallycoplanar with the first base surface 304.

As shown in FIG. 13B, the winding cup 306 defines a winding cupperiphery surface portion 322 on the first base surface 304. The hub topsurface 324 defines a hub periphery surface portion 326. The winding cupperiphery surface portion 322 and the hub periphery surface portion 326are those portions where a portion of the first conductive pattern 308is disposed on the respective surfaces.

The winding cup surface 309 defines a plurality of winding cup channels342 depending from the winding cup surface 309 and winding cup lands344, best shown in FIGS. 14A and 14B, each of which are continuous fromthe winding cup periphery surface portion 322 to the hub peripherysurface portion 326 of the hub top surface 324. As will be discussedbelow, each of the winding cup channels 342 will have conductivematerial disposed within so as to define a portion of an electricalcircuit.

The winding cup channels 342 may be produced in the winding cup 306 byany suitable method such as, but not limited to, machining and moldingprocesses. For example, a machining process may be used wherein thewinding cup 306 is provided in the base substrate 302 by a processseparate from the process of forming the winding cup channels 342. Inanother example, a molding process may be used wherein the winding cup306 and winding cup channels 342 are provided in the base substrate 302by the same process. A mold may be provided with features so as tosimultaneously create the winding cup 306 and winding cup channels 342.

FIGS. 14A and 14B are close-up detailed perspective views of the windingcup periphery surface portion 322 and the hub periphery surface portion326, respectively, in accordance with the embodiment of FIG. 13A. Thewinding cup channels 342 provide a surface upon which conductivematerial may be disposed so as to define a conductive pattern, as willbe described below. The winding cup lands 344 provide an electricallyinsulative separation between each winding cup channel 342. Theresulting first conductive pattern 308, shown in FIG. 13B, is alsoreferred herein as a “half winding”.

Referring again to FIGS. 13A and 13B, in accordance with an embodimentof a method to dispose conductive material into the winding cup channels342, an electrically conductive material is deposited onto the windingcup surface 309, including the winding cup lands 344. The depositionprocess may be any of a plurality of processes, such as, but not limitedto, plating and vapor deposition. The electrically conductive materialmay be any suitable material for the particular purpose, such as, butnot limited to, copper, gold and silver. It is appreciated that selectedregions of the base substrate 302 may be covered with the conductivematerial or substantially the entire base substrate 302 may be coveredwith the conductive material. The electrically conductive materialsubstantially coats the winding cup surface 309 but does not necessarilyhave to substantially “fill-in” the winding cup channels 342. Etchresist material, such as, but not limited to, that known in PCB andsemiconductor processing arts, is disposed over the conductive material.Many known techniques may be utilized to dispose the etch resistmaterial, such as, but not limited to, sprayed, dip coated, vacuumlaminated, electro-deposited, sputtering and thermal depositionprocesses.

FIGS. 15A and B are perspective and cross-sectional views, respectively,of a milling tool 385 in accordance with an embodiment. The milling tool385 may be used to preferentially remove etch resist material 397 fromthe winding cup lands 344, shown in FIG. 14A, so as to expose theconductive material 398 thereon. The milling tool 385 may be anysuitable tool suitable for the particular purpose, such as, but notlimited to a conventional end-mill cutter. In the embodiment of FIGS.15A-B, the milling tool 385 has one or more blades 386 that conform tothe winding cup surface 309 so as to remove the etch resist material 397and/or the conductive material 398 deposited on the winding cup lands344. It is understood that the blades 386 may facilitate a cutting orgrinding action so as to remove the etch resist material and/or theconductive material 398 deposited on the winding cup lands 344.

It is understood that etch resist material and/or conductive materialmay be removed from a substrate using any suitable process, such as butnot limited to, mechanical and chemical processes. Mechanical processesinclude, but not limited to, tools to affect grinding, cutting,abrading, milling and/or other mechanical removal process used tophysically remove the target material. Chemical processes include, butnot limited to, solvent, acid and aqueous solutions used to dissolve thetarget material.

Wherein only the etch resist material 397 is removed from the windingcup lands 344, the base substrate 302 is subsequently exposed to aprocess to remove the exposed conductive material 398 from the windingcup lands 344 so as to expose the base substrate material thereon. Thusis provided an insulative feature between each of the plurality ofwinding cup channels 342, each having conductive material 398 containedtherein defining a first conductive trace 328. Wherein the conductivematerial 398 does not substantially fill in the winding cup channel 342,leaving the etch resist material 397 on the conductive material 398 inthe winding cup channels 342 may serve as an electrical insulator whichmay be useful for electrically isolating the conductive material 398from the core.

A subsequent process, such as, but not limited to a mechanical orchemical process, to remove the remaining etch resist material 397 fromthe base substrate 302 may be performed so as to expose the conductivematerial 398 in the winding cup channels 342.

FIGS. 14C and 14D are close-up detailed perspective views of the windingcup periphery surface portion 322 and the hub periphery surface portion326, respectively, in accordance with the embodiment of FIG. 12. In theembodiments of FIGS. 14C and 14D, the winding cup channels 342 arefilled-in with either conductive material 398 or etch resist with anunderlying layer of conductive material.

By way of example, wherein the winding cup 306, as shown in FIG. 13A,defines an oval or other geometric shape, an end-mill tool, for example,may be utilized to remove the etch resist material 397 from the windingcup lands 344.

FIG. 16 is a cross-sectional view of an abrasive tool 387 and workpiece, in accordance with an embodiment. Wherein the first base surface304 is substantially planar, an abrasive tool 387 may be used to removethe etch resist material 397 from those features thereon. Such anabrasive tool 387 may be, such as, but not limited to, a roller sander,orbital sander, disc sander, wire brush and other abrasive tool usefulfor the removal of the etch resist material 397.

Referring also to FIG. 13B, in accordance with an embodiment, after theremoval of the etch resist material 397 from the winding cup lands 344,the method further comprises removing the conductive material 398 thatis exposed on the winding cup lands 344 by use of a suitable method,such as, but not limited to those methods associated with etching. Afterthe exposed conductive material 398 is substantially removed from thewinding cup lands 344, a first conductive pattern 308 that isthree-dimensional and electrically conductive comprises a plurality offirst conductive traces 328 that are discontinuous and radiate fromabout the axis 107 is defined. The first conductive traces 328 aredisposed from the hub periphery surface portion 326 to the winding cupperiphery surface portion 322 along the winding cup channels 342 therebetween. Each of the first conductive traces 328 comprise a trace hubend 327 that is associated with the winding cup periphery surfaceportion 322 and a trace winding cup periphery end 325 that is associatedwith the hub periphery surface portion 326, also shown in FIGS. 14C and14D. In accordance with an embodiment, the first conductive pattern 308is a “half winding” of an inductive device. As will be explained below,the resulting half winding will be associated with a complementaryconductive pattern so as to produce a complete winding-type electriccircuit structure.

FIGS. 13C and 13D are bottom and bottom perspective views of the basesubstrate 302, in accordance with the embodiment of FIG. 12. In thisembodiment, the hub 320, as shown in FIG. 13A, is hollow; that is, a hubrecess 350 depends from the second base surface 305 having an axissubstantially coaxial with that of the hub 320 defining a hub recesssurface 358 and a hub recess bottom surface 356. The hub recess surface358 is provided with hub recess channels 352 substantially similar tothose of the winding cup surface 309 of FIG. 13A, that extend from thehub recess bottom surface 356 to the second base surface 305. The hubrecess surface 358 defines the plurality of hub recess channels 352depending from the hub recess surface 358 defining hub recess lands 354.Radiating from each of the hub recess channels 352 is a second basesurface channel 370 that terminates at a second base surface secondchannel end 371.

An electrically conductive material 398 is disposed in the hub recesschannels 352 and the second base surface channels 370 so as to define aplurality of secondary conductive traces 368 of a secondary windingpattern 366 terminating at a secondary conductive trace first end 367and a secondary conductive trace second end 369. The deposition of theelectrically conductive material 398 is substantially similar to theprocess for depositing the conductive material 398 disposed in thewinding cup channels 342 of FIG. 13A. The hub recess lands 354 are voidof conductive material 398 so as to provide an electrically insulatingfunction between the hub recess channels 352. The resulting secondarywinding pattern 366 defines a portion of a secondary winding.

The second conductive traces 338 of the secondary winding pattern 366are electrically interconnected on the first base surface 304 of FIG.13A with complementary conductive traces or circuitry by electricalinterconnects, referred to herein as vias, that transcend through thebase substrate 302. Referring to FIGS. 13B, 14A and 14C, second end vias380 are provided that extend from the first base surface 304 adjacentthe winding cup 306 through to the second base surface 305 intersectingthe second base surface second channel end 371 and therefore the secondconductive trace second end 339, as shown in FIG. 13D. As shown in FIGS.14A and 14C, a winding cup periphery pad 391 may be formed within a paddepression 393 into which conductive material may be disposed. At thefirst base surface 304, the second end via 380 terminates at a windingcup periphery pad 391. The winding cup periphery pad 391 may provide agreater surface area to affect electrical interconnection withcomplementary conductive traces. The second end via 380 may be disposedin the base substrate 302 by any known method. By way of example, amethod known in the art involves drilling a bore from one surface toanother and coating the inside of the bore or filling the bore withelectrically conductive material providing an electrical conduit therebetween.

Similarly, electrical interconnects are provided on the hub 320.Referring to FIGS. 13B, 13D, 14B and 14D, hub vias 383 are provided aselectrical interconnects that extend from the hub top surface 324through to the hub recess bottom surface 356 intersecting the secondaryconductive trace first end 367, as shown in FIGS. 13C and 3D. At the hubtop surface 324, the hub vias 383 terminates at a hub pad 394. The hubpad 394 may provide a greater surface area to affect electricalinterconnection with complementary conductive traces. The hub vias 383may be disposed in the base substrate 302 by any known method asdescribed above.

As shown in FIGS. 14B and 14D, the hub pad 394 may be formed within apad depression 393 into which conductive material may be disposed. It isunderstood that the configuration of the end of the hub vias 383 may bemodified suitable for a particular purpose. The end of the hub vias 383may be flush with the respective surface or may be recessed. Similarly,if a hub pad 394 is provided, the hub pad 394 may be flush with therespective surface or may be recessed suitable for a particular purpose.

FIG. 17 is a top perspective view of an assembly 303 comprising the basesubstrate 302 and a core 110 disposed within the winding cup 306 of theembodiment of FIG. 12. In the embodiment of FIG. 17, the core 110 has atoroidal shape that corresponds to the shape of the winding cup 306. Itis understood that other core shapes, including, but not limited to,square and oval, may be used is a complementary-shaped winding cup.

Although the core 110 and the winding cup 306 may, in some embodiments,have a complimentary close fit, a gap 142 may be defined there between.In accordance with further embodiments, an encapsulate material that iselectrically insulative is disposed within the gap 142 between the core110 and the winding cup 306. Suitable encapsulate materials are known inthe art and include, but not limited to, certain types of epoxy fillmaterial. Filling the gap 142 may provide a number of benefits, such as,but not limited to, centering the core 110 within the winding cup 306,electrically insulating the core 110 from the first conductive patterns308, and fixing the position of the core 110 to prevent movementthereof.

FIG. 18 is a top perspective view of a magnetic device 301 comprisingthe base substrate 302 and the second substrate 312, in accordance withan embodiment. Also referring to FIGS. 12, 13A and 13B, after the core110 is disposed within the winding cup 306, unless an air-core is used,the second substrate 312 is coupled to the first base surface 304 of thebase substrate 302 and in complementary alignment with the firstconductive pattern 308. The first conductive pattern 308 on the firstbase surface 304 and the second conductive pattern 316 on the secondsubstrate second surface 314 are caused to become into electricalcommunication with each other so as to define a primary winding, as willbe described below. In accordance with embodiments, vias are providedwithin the second substrate 312 that extend from the second conductivepattern 316 on the second substrate 312 to the second substrate firstsurface 315 to the first conductive pattern 308 on the winding cup 306.The vias comprise an electrically conducting material so as to formelectrical interconnects between the first conductive pattern 308 andthe second conductive pattern 316.

Vias are known in the art as an element that transcends one or moreinsulative layers or substrates (such as circuit boards) so as tointerconnect electrical elements thereon. In accordance to embodiments,vias are produced by any method suitable, such as, but not limited to,drilling, and then plating or filling the resulting bore with anelectrically conductive material. The electrically conductive materialprovides an electrical interconnect between the respective conductivepatterns. It is understood that the configuration of the end of the viamay be modified suitable for a particular purpose. The end of the viamay be flush with the respective surface or may be recessed. Similarly,if a pad is provided, the pad may be flush with the respective surfaceor may be recesses suitable for a particular purpose.

The second conductive pattern 316 is operable to be associated with thefirst conductive pattern 308 on the hub periphery surface portion 326and the winding cup periphery surface portion 322 shown in FIG. 13B. Inaccordance with embodiments, trace hub end 327 is electrically coupledto the second conductive trace first end 337 and the trace winding cupperiphery end 325 is electrically coupled to the second conductive tracesecond end 339.

The second conductive pattern 316 comprises a plurality of secondconductive traces 338 that are discontinuous and radiate from about theaxis 107. The second conductive traces 338 comprise a second conductivetrace first end 337 positioned closest to the axis 107 and a secondconductive trace second end 339, opposite the second conductive tracefirst end 337. The number of second conductive traces 338 is determinedby the number of first conductive traces 328 and for a particularpurpose. In accordance with embodiments, including that shown in FIG.12, the number of second conductive traces 338 is equal to the number offirst conductive traces 328. In the embodiment of FIG. 12, the secondconductive traces 338 radiate from about the axis 107 such that a secondconductive trace first end 337 is aligned above a trace hub end 327,shown in FIG. 14D, of a first conductive trace 328, and a secondconductive trace second end 339 is aligned above a trace winding cupperiphery end 325 of an adjacent first conductive trace 328, shown inFIG. 14C, when the second conductive pattern 316 and the secondsubstrate 312 are coupled to the base substrate 302.

It is appreciated that the second substrate 312 including the secondconductive pattern 316 may be provided by any of a number of methods.For example, in the previous embodiment the second substrate 312 may beprovided as a unitary element in the form of a printed circuit boardthat may be coupled to the first base surface 304 of the base substrate302 using a laminating process. In other embodiments, the secondsubstrate 312 and the secondary winding pattern 366 may be coupled tothe base substrate 302 in separate processes. For example, the secondsubstrate 312 may be an electrically insulative layer that is molded,sprayed or printed onto the first base surface 304 of the base substrate302 and over any encapsulate material and the core 110. The secondconductive pattern 316 may subsequently be molded, sprayed or screenprinted onto the second substrate 312, for example.

In accordance with embodiments, the second substrate 312 is a printedcircuit board (PCB) having a second conductive pattern 316 that iscomplementary to the first conductive pattern 308 of the winding cup306. As with the base substrate 302, similar processes may be used toprovide the second conductive pattern 316. For example, but not limitedthereto, the second conductive pattern 316 may be produced using aplating technique or a layering technique, wherein a plated metallicsurface or a thin layer of conductive material may be applied in asubsequent plating step. In another example, not limited thereto, theconductive material may be provided as a plating layer that isphoto-imaged and etched using conventional printed circuit assemblytechniques.

Multiple substrate and conductive layers may be added, as warranted bythe design.

FIG. 19 is a top perspective view of a magnetic device 300 of theembodiment of FIG. 12, comprising the base substrate 302, the secondsubstrate 312, and the top substrate 372. The secondary conductivetraces 368 of the secondary winding pattern 366, shown on FIG. 13D, areelectrically interconnected on the first base surface 304 with the topconductive traces 378 of the top conductive pattern 376 disposed on thetop substrate second surface 374 which is opposite from the topsubstrate first surface 373. Substantially as described previously forthe electrical interconnection of the secondary conductive traces 368with the second conductive traces 338, vias are provided so as toelectrically interconnect the top conductive traces 378 with thesecondary conductive traces 368. Vias are provided to interconnect thetop conductive trace first end 375 with the hub pad 394, shown in FIG.14D, and to interconnect the top conductive trace second end 377 withthe winding cup periphery pad 391 shown in FIG. 14C. The vias passthrough the top substrate 372 and the second substrate 312 to therespective pad.

Referring again to FIGS. 18 and 19, the first conductive pattern 308 onthe base substrate 302 and the second conductive pattern 316 on thesecond substrate 312 are operable to electrically define a primarywinding of a magnetic device 300 of FIG. 12. The second end vias 380 inthe base substrate 302 and the top conductive pattern 376 on the topsubstrate 332 are operable to electrically define a secondary winding ofthe magnetic device 300.

As described previously for the embodiments of FIGS. 5A-10B, thephysical characteristics of the interconnected circuit patterns for themagnetic device 301, determines the magnetic device's electricalcharacteristics; for example, whether the magnetic device is aninductor, transformer or other type of component having thefunctionality of a conventional wire-wound configuration.

As shown in FIG. 12, the second conductive pattern 316 and correspondingfirst conductive pattern 308 comprises a much denser winding than thetop conductive pattern 376 and corresponding secondary winding pattern366. The winding density ratio “n” of the primary and secondarywindings, respectively, may vary suitable for a particular purpose. FIG.12 illustrates an embodiment wherein there is a large winding densityratio between the primary and secondary windings. By way of examples,but not limited thereto, in power converter designs, step-downtransformers are used, such as to convert from 120V to 24V or 48V to12V. The voltage step-down is determined, in part, by the winding ratiobetween the primary and secondary windings. Step-up transformers arealso useful. Step-up transformer functionality may be provided byembodiments presented herein.

It is noted that FIG. 12 only depicts a second substrate 312 and a topsubstrate 372 being disposed on and coupled to a base substrate 302. Itis appreciated that more substrates may be provided, as warranted by thedesign suitable for a particular purpose.

As explained above, embodiments of magnetic devices in accordance withthe claimed subject matter contain one or more winding-type electriccircuits (windings); that is, the electrical interaction of theelectrically interconnected conductive patterns form, in effect, one ormore winding-type electric circuit structures surrounding the core. Asprovided above, electrical properties of the windings may be manipulatedand predetermined by the physical characteristics of the conductivepatterns. By way of example, the dimensions of thickness and width ofthe conductive patterns may be predetermined so as to provide a desiredelectrical characteristic. In addition, the resistance and/or ACimpedance of the windings may be controlled by the preselectedconfiguration of the vias, such as, but not limited to, the size, shapeand number of the vias.

By way of example, FIG. 20 is a top view of the second conductive tracesecond end 339 of the second conductive pattern 316 as a detailed view20 in FIG. 18, in accordance with an embodiment. Each of the secondconductive trace second ends 339 is provided with a first via 340 havinga predetermined shape, in this case an oval that is predetermined toprovide a desired electrical resistance and/or impedance as describedpreviously. The first via 340 provides an electrical interconnectbetween the second conductive trace first end 337 of the secondconductive trace 338 and the trace hub end 327 of the first conductivetrace 328 as shown in FIG. 13B.

By way of another example, FIG. 21 is a top view of the secondconductive trace second end 339 of the second conductive pattern 316 asa detailed view 21 shown in FIG. 18, in accordance with an embodiment.Each of the second conductive trace second ends 339 is provided with aplurality of vias 341, in this example there are two, the number andsize of which are predetermined to provide a desired electricalresistance and/or impedance.

The plurality of vias 341 may be used to electrically interconnect thesecond conductive trace second end 339 of the second conductive trace338 to the trace winding cup periphery end 325 on the base substrate 302shown in FIG. 13B.

In accordance with other embodiments, the base substrate may comprisecavities, such as within the hub and adjacent the winding cup. Thesecavities may assist in the molding process if such is used formanufacturing the base substrate. In other embodiments, the cavities maybe filled with various materials so as to affect performancecharacteristics. In accordance with an embodiment, by way of example, amaterial having a high thermal conductivity may be disposed in a cavityin the hub to provide passive thermal management so as to conduct heatfrom the windings under an electrical load away from the magneticdevice.

Embodiments of the embedded magnetic device support verticalintegration. Voids and cavities may be provided in the base substrate toreceive passive and active components that may be used in theapplication circuit. For example, holes may be molded into the basesubstrate operable to receive electrolytic capacitors packaged in a“can”-style package known in the art. Similarly, cavities may beprovided and selectively plated with an electrically conductive materialand operable to receive active and passive surface-mount components.

FIG. 22 is a flow diagram of an embodiment of a method 30 of making amagnetic device, in this embodiment, an inductive device. It isunderstood that the particular embodiment may be used to make a varietyof magnetic devices having a wire-wound characteristic. The methodcomprises providing a base substrate having a first surface defining awinding cup including a hub, the winding cup including grooves and lands32; depositing an electrically conductive layer within and about thewinding cup and hub 34; applying an etch resist material to theconductive layer 36; removing the etch resist material from the landsusing mechanical means exposing the conductive layer from the lands 38;removing the exposed conductive layer from the lands, the remainingconductive layer defining a first conductive pattern 40; disposing acore in the winding cup 42; providing a second substrate having a secondconductive pattern 44; disposing the second substrate onto the firstsurface of the base substrate covering the core 46; and providing meansfor electrically interconnecting the first conductive pattern with thesecond conductive pattern 48.

It is appreciated that the fabrication process is scalable allowing theprocess to serve a variety of core sizes. A molding process forfabricating the winding cup may be used to produce relatively deepwinding cup structures which may be very challenging or impossible toproduce when using imaging, printing, sputtering, laser structuring andother techniques for producing three-dimensional circuits.

In accordance with embodiments of methods of the claimed subject matter,a batch process may be used for manufacturing winding toroidal corestructures. These methods provide a distinct advantage over hand ormachine wire-wound electrical components. Prior-art processes forproducing transformers and inductors, for example, provide wire that iswound on larger and costlier E and C core structures due to thefabrication process of winding a bobbin with wire and clamping a corearound it. Embodiments in accordance with the claimed subject matterprovide methods for fabricating toroidal-shaped components that have arelatively smaller form-factor using relatively low cost and simpleprocesses. In many electrical applications, toroidal-shaped componentsmay be more efficient than E and C clamped cores. Additionally,toroidal-based devices may have less secondary parasitic parameters,such as, but not limited to, leakage inductance and inter-windingcapacitance. In accordance with embodiments of the claimed subjectmatter, the embedded magnetic devices and fabrication process allows forthese secondary effects to me minimized. In addition, the structureeasily supports the inclusion of electromagnetic shielding and thermalheat sinks.

Embodiments of methods of the claimed subject matter provide processesthat may produce conductive patterns that are used to producewinding-type electrical circuits (windings) that are very repeatable tohigh electrical tolerances, assisting in the production of deviceshaving consistent performance characteristics.

In an embodiment, a multi-layer structure that supports conductors ofdifferent geometries and provides high voltage isolation between primaryand secondary windings is provided.

In an embodiment, milling tools are provided that have a specificprofile that is the converse of a predefined winding cup and canefficiently remove etch resistance material from the raised surfaces,such as the winding channel lands.

Methods in accordance with embodiments provide a process that is usefulfor producing inductors and transformers for sensors, communications andpower applications, but not limited thereto.

As previously discussed, embodiments of the magnetic device include aferromagnetic core disposed in the winding cup. Embodiments of theclaimed subject matter include methods for producing ferromagnetic coresoperable for disposition in winding cups.

FIG. 23 is a top perspective view of a circular toroidal core 110 acomprising a circular bore 165 a, core inner sidewall 164 a and coreouter sidewall 162 a that are complementary to the feature wall surface109 of the embodiment of FIG. 1B, in accordance with an embodiment. Thecore inner sidewall 164 a being complimentary to the feature inner wall119 and the core outer sidewall 162 a being complimentary to the featureouter wall 129 provide, when assembled, a close proximity between thefirst conductive pattern 108 and the core 110 a. The close proximitybetween the first conductive pattern 108 and the core 110 a isimportant, for example, for optimizing inductive coupling and affectinga magnetic flux within the core 110 a during operation. Referring toFIG. 1C, the core inner sidewall 164 a and core outer sidewall 162 a ofthe core 110 a are tapered to assist in self-alignment of the core 110 awithin the feature 106.

In accordance with embodiments, the core 110 a is fixed in place withinthe feature 106 a with an electrically insulative potting material, suchas, but not limited to, an electrically insulative epoxy material. Theelectrically insulative material should have a thermal expansioncoefficient complementary with that of the base substrate and the core110 a such that minimal movement of the core 110 a when the magneticdevice is subjected to operational and environmental thermal conditions.

In accordance with embodiments, the core inner sidewall 164 a and coreouter sidewall 162 a are substantially complementary to the featureinner wall 119 and the feature outer wall 129 so as to minimize the gap142 there between. Wherein the gap 142 is minimized, a minimum amount ofelectrically insulative material may be used within the gap 142. A gap142 of minimal dimensions and a minimal amount of electricallyinsulative material is advantageous for a number of reasons, one ofwhich may be to minimize the effects of thermal expansion mismatchbetween the base substrate, electrically insulative material, and thecore 110 a.

FIG. 24 is a top perspective view of an oval-shaped core 110 b with anoval bore 165 b, a core inner sidewall 164 b and a core outer sidewall162 b that are tapered, in accordance with an embodiment. Advantages ofan oval shape for the oval-shaped core 110 b will be discussed furtherbelow.

FIG. 25 is a top perspective view of a plurality of circular toroidalcores 110 a and oval-shaped cores 110 b disposed within respectivefeature 106 a and oval-shaped features 106 b, respectively, of a basesubstrate 102 m, in accordance with an embodiment. Once the plurality ofcircular toroidal cores 110 a and oval-shaped cores 110 b are seatedwithin the respective features 106 a and oval-shaped features 106 b, asecond substrate comprising a conductive layer is disposed upon the basesubstrate 102 m substantially as discussed above.

It is appreciated that the shape of the ferromagnetic core impartsspecific electrical characteristics to the magnetic device. Themodularity of the embodiments of the claimed subject matter providesthat ability to produce ferromagnetic cores of various geometries. Forexample, but not limited thereto, an oval, binocular orrectangular-shaped cores.

FIG. 26 is a top perspective view of a core 110 c that has an oval shapeand includes two bores 165 c, referred to as a binocular core, inaccordance with an embodiment. This core would be complimentary with afeature having a complimentary shape with two hubs.

FIG. 27 is a top perspective view of a core 110 d that has a rectangularshape and includes a rectangular bore 165 d. This core 110 d would becomplimentary with a feature having a complimentary rectangular shapewith a rectangular hub.

FIG. 28 is a top perspective view of a core 110 e that has a rectangularshape and includes two square bores 165 e, in accordance with anembodiment. This core 110 e would be complimentary with a feature havinga complimentary rectangular shape with two hubs. Embodiments of theclaimed subject matter provide a means to provide simple or complexmagnetic devices having winding features.

Referring again to FIG. 24, the oval bore 165 b may be useful toincrease the bore as compared with the circular bore 165 a shown in FIG.23, and correspondingly allow for an increase in the number of windings(which is dependent on the pattern spacing allowed by the hub), such asmight be beneficial in a transformer or inductor device. Increasing thenumber of conductive pattern windings provided on the hub effectivelyincreases the effective winding count, referring to an equivalent numberof windings of a wire in wire-wound components.

The larger bore opening also allows the use of larger conductor patterngeometries for the windings. The oval shape can also have a largermagnetic path length versus a circular shape, which is a parameter thatmay be used to manage the magnetic flux within the core.

The oval or rectangular shaped core with a larger path length in one ofthe length or width may reduce the core's susceptibility to magneticsaturation due to magnetic flux. Ferromagnetic materials have specificsaturation points dependent on their specific material composition.Wherein there is too much induced magnetic flux, the material maymagnetically saturate and its ability to store and transferelectromagnetic energy may be diminished. Magnetic saturation may alsobe exacerbated by thermal stress and mechanical stress. In general, thelonger magnetic path length of an oval shaped core increases themagnetic flux that may be contained in the core and reduce the core'ssusceptibility to magnetic saturation. This longer path length, largercore volume and reduced susceptibility to magnetic saturation alsostabilizes the core's performance under mechanical and thermal stressenvironments.

Powered applications of wire-wound type devices often require a mix ofwire gauges, different winding segments and different winding ratios.They also often require that taps, also referred to as conductivetake-offs, that are pulled, a term in the art for coupled, from thewinding to provide electrical connections intermediate to the winding.Embodiments of claimed subject matter, providing the “winding” in theform of conductive pattern, may facilitate methods for, such as, but notlimited to, applying conductive patterns to a toroidal core device,controlling the resistance of the conductive patterns, allowing forlarge conductive pattern ratios, and pulling intermediate taps.

In accordance with embodiments of the disclosed subject matter, theconductive patterns may have varying or different effective gauge valuessuitable for a particular purpose. Effective gage, used herein, refersto a wire gage equivalent. Where one circuit including a conductivepattern requires a larger current carrying capacity indicative of alarger gauge wire, the conductive pattern may be predetermined toprovide that capability by predetermining the physical dimensions of thetraces for a specific conductive material. The methods of producingmagnetic devices in accordance with embodiments facilitate multiplecircuits including a conductive pattern of a magnetic device wherein theeffective gauge of one circuit including a conductive pattern may not bedependent on the effective gauge of another circuit including anotherconductive pattern. By way of example, referring to FIGS. 6A and 6B, thecircuit comprising W1A and W1B many have a different effective gauge orcurrent carrying capacity than the circuit comprising W2A and W2B.

Another advantage, by way of example but not limited thereto, of theclaimed subject matter is that, for particular electromagnetic devices,the more preferred toroidal core geometry may be used. For example, thetoroidal shape may be a more efficient geometry to transferelectromagnetic energy between windings. In wire-wound deviceproduction, the toroidal core geometry is difficult to wind with wire.In some cases, the less effective C and E core geometry may be used asbeing more conducive to bobbin winding production incorporatingdifferent gauge wires, winding taps and large winding ratios, forexample. Embodiments of the disclosed subject matter provide anefficient and effective means for producing the desired electromagneticdevices without some of the design-limiting production limitations of awire-winding process.

Although magnetic devices such as provided by apparatus and methodspresented herein may be used in a vast number of electronic componentsand devices, by way of example, they are particularly advantageous inthe construction of wideband data communication transformers and powerelectronics. The apparatus presented herein allows for optimization ofperformance by keeping the circuit windings and core in close proximityto one another.

In the embodiments of FIGS. 1-21, windings, such as the primary andsecondary windings of a transformer, are affected by the use, at leastin part, of metalized traces either on a surface of a feature or withinchannels defined by the feature, also referred to as a winding cup. Themetalized traces are electrically interconnected with traces on surfacesof various substrates by use of vias so as to define one or morewindings.

In accordance with the following embodiments, described as embodimentsof FIGS. 29-43 b, apparatus and methods are provided herein forproviding and assembling magnetic devices and magnetic components,wherein windings, such as the primary and secondary windings of atransformer, are defined by the use, at least in part, of plated throughhole (PTH) vias adjacent to the feature. The vias are electricallyinterconnected with traces on surfaces of various substrates so as todefine one or more windings about one or more cores.

In accordance with embodiments, arrayed embedded magnetic componentsinclude magnetic devices that have a core that is embedded between twoor more substrates and a winding pattern surrounding the core that isimplemented on and through the two or more substrates. The windingpattern is operable to induce a magnetic flux within the core whenenergized by a time varying voltage potential. The winding pattern maybe implemented by printed circuit layers, plated vias, otherelectrically conductive elements, and combinations thereof. Arrayedembedded magnetic components include two or more magnetic deviceselectrically connected in parallel or series or combinations thereof,and positioned side-by-side in a horizontal integration defining ahorizontal array, positioned coaxially in a vertical integrationdefining a vertical array, or combinations thereof. The magnetic devicesmay have a magnetic functionality such as, but not limited to, atransformer, inductor, and filter. In accordance with embodiments,magnetic components and methods provide for low cost construction,consistent performance, and a low profile form, among other benefits.

The term core cavity is used herein to identify a feature that does notdefine conductive traces. The term core cavity is used to differentiatebetween a feature defining conductive traces such as the winding cup 306of FIG. 13A-13B. The core cavity and winding cup are both operable toreceive a core therein. The core cavity and winding cup are described inthe following embodiments as defining a closed groove. The term closedgroove is used herein as a groove that has no beginning or ending, suchas having an axial projection in a form of a circle, oval, or square, ascompared to an open groove having a distinct beginning and ending suchas having an axial projection in the form of a line. It is understoodthat other shapes of core cavities are anticipated, such as a corecavity having a straight groove operable to receive a rod-shaped core.

It is appreciated that winding circuitry of magnetic components may alsobe affected by using a combination of metalized traces on the surface ofa feature or within channels defined by the feature and PTH-type viasthat are adjacent to the feature.

Vias, as used herein may be one of a number of types of vias. Blind vias(BV) are used to electrically connect an outer conductor trace or layerto an inner conductor trace or layer, such as shown in FIG. 1B, asinterconnects 140. A plated through hole (PTH) via passes though thesubstrate as shown in FIGS. 13B, C, D, second end via 380 and hub via383. A buried via electrically connects two internal adjacent conductortraces or layers; however, it may electrically connect more than twointernal conductor traces or layers. Vias of various types are wellknown in the art.

FIG. 29 is a perspective exploded view of a plated through hole (PTH)construction of an embedded magnetic device 400 in accordance with anembodiment. The embedded magnetic device 400 comprises a base substrate402, a second substrate 422, a third substrate 432, and a core 410. Thebase substrate 402 defines a base substrate first surface 405 and a basesubstrate second surface 404 opposite the base substrate first surface405. The base substrate second surface 404 comprises a core cavity 431depending from the base substrate second surface 404 having a shape of aclosed groove surrounding a hub 420, such as, but not limited to agroove of revolution. The hub 420 defines a hub top surface 124 that issubstantially coplanar with the base substrate second surface 404. Thecore cavity 431 is operable to receive the core 410 therein, such asshown for the embodiment of FIG. 30. The base substrate 402 furthercomprises a plurality of first base vias 492 in the form of platedthrough holes (PTH) adjacent a perimeter of the core cavity 431 andextending from the base substrate second surface 404 to the basesubstrate first surface 405. The hub 420 further comprises a pluralityof hub perimeter vias 482 in the form of plated through holes (PTH)adjacent a hub perimeter 481 of the hub 420 and extending from the hubtop surface 124 to the base substrate first surface 405.

The second substrate 422 is substantially similar to the secondsubstrate 112 of the embodiment of FIGS. 1A and 1B. The second substrate422 comprises a second substrate first surface 425 and a secondsubstrate second surface 424 opposite the second substrate first surface425. A second conductive pattern 426 is disposed on the second substratesecond surface 424. Second substrate first vias 488 and second substratesecond vias 483 extend from the second conductive pattern 426 throughthe second substrate 422 to the second substrate first surface 425. Thesecond substrate first surface 425 is disposed on and coupled to thebase substrate second surface 404, with the second conductive pattern426 in coaxial, about axis 107, and complimentary alignment with thecore cavity 431. The second substrate first vias 488 are incomplimentary alignment with the first base vias 492, and the secondsubstrate second vias 483 are in complimentary alignment with the hubperimeter vias 482. Complimentary alignment as referred to herein meansin a relationship that will affect electrical interconnection and/ormagnetic properties.

The third substrate 432 is substantially similar to the second substrate422. The third substrate 432 comprises a third substrate first surface435 and a third substrate second surface 434 opposite the thirdsubstrate first surface 435. A third conductive pattern 436 is disposedon the third substrate second surface 434, shown in phantom in FIG. 29.Third substrate first vias 485 and third substrate second vias 486extend from the third conductive pattern 436 through the third substrate432 to the third substrate first surface 435. The third substrate firstsurface 435 is disposed on and coupled to the base substrate firstsurface 405, with the third conductive pattern 436 in coaxial, aboutaxis 107, and complimentary alignment with the core cavity 431. Thethird substrate first vias 485 are in complimentary alignment with thefirst base vias 492, and the third substrate second vias 486 are incomplimentary alignment with the hub perimeter vias 482.

The second conductive pattern 426, the third conductive pattern 436, thesecond substrate first vias 488, the second substrate second vias 483,the third substrate first vias 485, the third substrate second vias 486,the first base vias 492, and the hub perimeter vias 482 comprise anelectrically conductive material. As will be further described below,the second conductive pattern 426 and the third conductive pattern 436are electrically interconnected with the second substrate first vias488, the second substrate second vias 483 the third substrate first vias485, the third substrate second vias 486, the first base vias 492, andthe hub perimeter vias 482 so as to electrically cooperate to beoperable for facilitating magnetic properties of the core 410 whenelectrically energized, in accordance with various embodiments.

It should be appreciated that FIG. 29 illustrates an exploded view todescribe an embodiment of the claimed subject matter, and accordingly,as will be described in further detail, the magnetic device 400 willhave the core 410 enclosed within the core cavity 431, with the secondsubstrate 422 covering and enclosing the core 410.

The second conductive pattern 426, the third conductive pattern 436, thesecond substrate first vias 488, the second substrate second vias 483the third substrate first vias 485, the third substrate second vias 486,the first base vias 492, and the hub perimeter vias 482 are electricallyinterconnected to define one or more electric circuits that surround thecore 410, thereby forming a winding-type relationship. The winding-typerelationship is such as associated with a winding-type electric circuitthat cooperates so as to induce a magnetic flux within the core 410 whenthe one or more electric circuits are energized by a voltage source.This type of relationship may be used to produce, by way of example, atransformer or inductor winding pattern. Such winding-type relationshipis similar in function to known electrical devices in the art thatcomprise a wire-wrapped core configuration. Embodiments of differentwinding-type relationships will be discussed below, but are not limitedthereto.

It is appreciated that, contrary to the core cavity 118 of theembodiment of FIG. 1B that requires tapered sides so as to allowdeposition of a conductive pattern on the tapered sides using imagingtechniques, the embodiment of the core cavity 431 of FIG. 29 may havestraight sides since plated through hole vias are used instead of adeposition of a conductive pattern on the sides of the core cavity 431.It is appreciated that embodiments presented herein may alternativelyuse a conductive pattern on the sides of the core cavity 431, as inFIGS. 1B and 12, instead of the plated through hole vias. It is alsoappreciated that embodiments having a combination of a conductivepattern on the sides of the core cavity, as in FIGS. 1B and 12, as wellas plated through hole vias that function as a winding, as in FIG. 29,may be used.

In accordance with an embodiment, and referring again to FIG. 29, thecore cavity 431 in the form of a cavity is disposed into the basesubstrate first surface 405 of the base substrate 402, using such as,but not limited to, machining and milling techniques. The first basevias 492, and the hub perimeter vias 482 may be produced by drillingthrough holes in the base substrate 402 and depositing conductivematerial within the through holes. The core 410, comprising aferromagnetic material, for example, but not limited thereto, isinserted into the core cavity 431 and encapsulated therein by anencapsulate material (not shown) that is electrically non-conductive,such as, but not limited to, silicone and epoxy.

The second substrate first surface 425 of the second substrate 422 isdisposed on and coupled to the base substrate second surface 404. Thesecond conductive pattern 426 is disposed, such as by, but not limitedto, imaging, on the second substrate second surface 424. The secondconductive pattern 426 comprises a plurality of second conductive traces489 that are discontinuous, that is, they don't touch each other. Thesecond substrate first vias 488 and the second substrate second vias 483are operable to electrically interconnect the second conductive traces489 and the underlying the first base vias 492 and the hub perimetervias 482, respectively. The second substrate first vias 488 and thesecond substrate second vias 483 may be produced by drilling throughholes in the second substrate 422 and depositing conductive materialwithin the through holes. The drilling may be done at a high ratereducing fabrication cost, among other benefits.

The third substrate first surface 435 of the third substrate 432 isdisposed on and coupled to the base substrate first surface 104. Thethird conductive pattern 436 is disposed on the third substrate secondsurface 434. The third conductive pattern 436 comprises a plurality ofthird conductive traces 487 that are discontinuous, shown in phantom inFIG. 29. The third substrate first vias 485 and third substrate secondvias 486 are operable to electrically interconnect the third conductivetraces 487 and the underlying first base vias 492 and the hub perimetervias 482, respectively. The third substrate first vias 485 and the thirdsubstrate second vias 486 may be produced by drilling through holes inthe third substrate 432 and depositing conductive material within thethrough holes.

In accordance with embodiments, winding inductance, impedance and powerdelivery may be managed by electrically interconnecting an array of twoor more magnetic devices in series or parallel, or combination, to forma magnetic component. FIG. 30 is a perspective exploded view of a firstmagnetic device 501 a and a second magnetic device 501 b each in atransformer configuration that are arrayed horizontally in the sameassembly sharing the same base substrate 502 to define a horizontalmulti-device embedded magnetic component 500, in accordance with anembodiment. In this implementation, two cores 410 are contained adjacentto each another in the same base substrate 502 in a horizontalintegration defining a horizontal array. The transformer primarywindings are implemented by the second substrate 522 and the thirdsubstrate 532. The transformer secondary windings are implemented by afourth substrate 542 and a fifth substrate 552. The circuit design onthe second substrate 522, the third substrate 532, the fourth substrate542 and the fifth substrate 552 determines whether the windings areconnected in either a series, parallel, or combination of series andparallel configuration.

Referring again to FIG. 30, the horizontal multi-device embeddedmagnetic component 500 comprises two embedded magnetic devices of thePTH type, a first magnetic device 501 a and a second magnetic device 501b, each of which substantially correspond to the embedded magneticdevice 400 of the embodiment of FIG. 29, in a side-by-side relationship,and sharing a same base substrate 502, sharing a same second substrate522 and sharing a same third substrate 532, and with a core 410 disposedin each core cavity 431 defined by the base substrate 502. Thehorizontal multi-device embedded magnetic component 500 furthercomprises a fourth substrate 542, and a fifth substrate 552, eachoperable to interconnect the first magnetic device 501 a and the secondmagnetic device 501 b in electrical communication, defining a horizontalmulti-device embedded magnetic component 500.

The base substrate 502 is substantially similar to the base substrate402 of FIG. 29, but with multiple core cavities 431. The base substrate502 defines a base substrate first surface 505 and a base substratesecond surface 504 opposite the base substrate first surface 505. Thebase substrate second surface 504 defines two core cavities 431 that areadjacent to each other on a horizontal plane defined by the basesubstrate second surface 504. Each core cavity 431 defines a closedgroove depending from the base substrate second surface 504 surroundinga hub 420, such as, but not limited to a groove of revolution.

The hub 420 defines a hub top surface 124 that is substantially coplanarwith the base substrate second surface 504. The core cavity 431 isoperable to receive the core 410 therein, as previously described forthe embodiment of FIG. 29. The base substrate 502 further comprises aplurality of first base vias 492 in the form of plated through holes(PTH) adjacent a perimeter of the core cavity 431 and extending from thebase substrate first surface 505 to the base substrate second surface504. The hub 420 further comprises a plurality of hub perimeter vias 482in the form of plated through holes (PTH) adjacent a hub perimeter 481of the hub 420 and extending from the hub top surface 124 to the basesubstrate first surface 505. The hub 420 further comprises a pluralityof hub second vias 584 of the plated through hole type inward from thehub perimeter vias 482 and extending from the hub top surface 124 to thebase substrate first surface 505.

Base substrate fourth vias 491 are located in predetermined locations onthe base substrate 502 so as to provide a pass-through connectionthrough the base substrate 502. The base substrate fourth vias 491extend from the base substrate second surface 504 through the basesubstrate 502 to the base substrate first surface 505.

It is appreciated that, contrary to the core cavity 431 of theembodiment of FIG. 1B that requires tapered sides so as to allowdeposition of a first conductive pattern 108 on the tapered sides, theembodiment of the core cavity 431 of FIG. 30 may have straight sidessince there is no deposition of a conductive pattern on the sides of thecore cavity 431. It is appreciated that embodiments having a conductivepattern on the sides of the core cavity 431, as in FIG. 1B, may be used.It is also appreciated that embodiments having a combination of aconductive pattern on the sides of the core cavity 431, as in FIG. 1B,as well as vias that function as a winding, as in FIG. 30, may be used.

The second substrate 522 is substantially similar to the secondsubstrate 422 of the embodiment of FIG. 29 but comprising two conductivepatterns instead of one. The second substrate 522 comprises a secondsubstrate first surface 525 and a second substrate second surface 524. Asecond substrate first conductive pattern 526 a and the second substratesecond conductive pattern 526 b are disposed on the second substratesecond surface 524.

Second substrate first vias 488 and second substrate second vias 483extend from the second substrate first conductive pattern 526 a andsecond substrate second conductive pattern 526 b through the secondsubstrate 522 to the second substrate first surface 525. Secondsubstrate third vias 585 are located inwardly from the second substratesecond vias 483 and are operable to align with the hub second vias 584.The second substrate third vias 585 extend from the second substratesecond surface 524 through the second substrate 522 to the secondsubstrate first surface 525.

Second substrate fourth vias 496 are located in predetermined locationson the second substrate 522 so as to provide a pass-through connectionthrough the second substrate 522 and are not associated with theconductive patterns on the second substrate. The second substrate fourthvias 496 extend from the second substrate second surface 524 through thesecond substrate 522 to the second substrate first surface 525.

The second substrate first surface 525 is disposed on and coupled to thebase substrate first surface 505 with the second substrate firstconductive pattern 526 a and the second substrate second conductivepattern 526 b in coaxial, about axis 107 a and axis 107 b, respectfully,complimentary alignment with respective core cavities 431 and respectivecores 410 of the base substrate 502. The second substrate first vias 488are in complimentary alignment with the first base vias 492, the secondsubstrate second vias 483 are in complimentary alignment with the hubperimeter vias 482, and the second substrate third vias 585 are incomplimentary alignment with the hub second vias 584. Complimentaryalignment as referred to herein means in a relationship that will affectelectrical interconnection and/or magnetic properties.

The third substrate 532 is substantially similar to the third substrate432 of the embodiment of FIG. 29, but comprising two conductive patternsinstead of one. The third substrate 532 comprises a third substratefirst surface 535 and a third substrate second surface 534. A thirdsubstrate first conductive pattern 536 a and a third substrate secondconductive pattern 536 b, shown in phantom, are disposed on the thirdsubstrate second surface 534.

Third substrate first vias 485 and third substrate second vias 486extend from the third substrate first conductive pattern 536 a and athird substrate second conductive pattern 536 b through the thirdsubstrate 532 to the third substrate first surface 535. Third substratethird vias 586 are located inwardly from the third substrate second vias486 and are operable to align with the hub second vias 584. The thirdsubstrate third vias 586 extend from the third substrate second surface534 through the third substrate 532 to the third substrate first surface535. Third substrate fourth vias 497 are located in predeterminedlocations on the third substrate 532 so as to provide a pass-throughconnection through the third substrate 532 and are not associated withthe conductive patterns on the third substrate. The third substratefourth vias 497 extend from the third substrate second surface 534through the third substrate 532 to the third substrate first surface535.

The third substrate first surface 535 is disposed on and coupled to thebase substrate first surface 505, with the third substrate firstconductive pattern 536 a and a third substrate second conductive pattern536 b in coaxial, about axis 107 a and axis 107 b, respectfully,complimentary alignment with respective core cavities 431 and respectivecores 410 of the base substrate 502. The third substrate first vias 485are in complimentary alignment with the first base vias 492, the thirdsubstrate second vias 486 are in complimentary alignment with the hubperimeter vias 482, and the second substrate third vias 585 are incomplimentary alignment with the hub second vias 584. Complimentaryalignment as referred to herein means in a relationship that will affectelectrical interconnection and/or magnetic properties.

The fourth substrate 542 comprises a fourth substrate first surface 545and a fourth substrate second surface 544. A fourth conductive pattern547 is disposed on the fourth substrate second surface 544. The fourthconductive pattern 547 comprises a fourth substrate first conductivesub-pattern 541 a and a fourth substrate second conductive sub-pattern541 b that are electrically interconnected.

Fourth substrate first vias 588 and fourth substrate second vias 583extend from the fourth substrate first conductive sub-pattern 541 a andfourth substrate second conductive sub-pattern 541 b through the secondsubstrate 522 to the fourth substrate first surface 545. Fourthsubstrate third vias 589 are located on the fourth substrate 542 to beoperable to interconnect with underlying circuitry, such as, by way ofexample, to provide an electrical interface from the fourth substratesecond surface 544 to the second substrate second conductive pattern 526b, as shown in FIG. 30, to allow connection with external electronics,for example. The fourth substrate third vias 589 extend from the fourthsubstrate second surface 544 through the fourth substrate 542 to thefourth substrate first surface 545.

The fourth substrate first surface 545 is disposed on and coupled to thesecond substrate second surface 524 with the fourth substrate firstconductive sub-pattern 541 a and the fourth substrate second conductivesub-pattern 541 b in coaxial complimentary alignment with the secondsubstrate first conductive pattern 526 a and the second substrate secondconductive pattern 526 b respectively, about axis 107 a and axis 107 b,respectfully.

The fourth substrate first vias 588 are in complimentary alignment withthe second substrate fourth vias 496, the base substrate fourth vias491, and the third substrate fourth vias 497. The fourth substratesecond vias 583 are in complimentary alignment with the second substratethird vias 585, the hub second vias 584, and the third substrate thirdvias 586. Complimentary alignment as referred to herein means in arelationship that will affect electrical interconnection and/or magneticproperties.

The fifth substrate 552 comprises a fifth substrate first surface 555and a fifth substrate second surface 554. A fifth conductive pattern 548is disposed on the fifth substrate second surface 554, shown in phantom.The fifth conductive pattern 548 comprises a fifth substrate firstconductive sub-pattern 549 a and a fifth substrate second conductivesub-pattern 549 b that are electrically interconnected.

Fifth substrate first vias 591 and fifth substrate second vias 592extend from the fifth substrate first conductive sub-pattern 549 a andfifth substrate second conductive sub-pattern 549 b through the fifthsubstrate 552 to the fifth substrate first surface 555. Fifth substratethird vias 587 are located on the fifth substrate 552 to be operable tointerconnect with underlying circuitry, such as, by way of example, toprovide an electrical interface from the fifth substrate second surface554 to the third substrate first conductive pattern 536 a, as shown inFIG. 30, to allow connection with external electronics, for example. Thefifth substrate third vias 587 extend from the fifth substrate secondsurface 554 through the fifth substrate 552 to the fifth substrate firstsurface 555.

The fifth substrate first surface 555 is disposed on and coupled to thethird substrate second surface 534 with the fifth substrate firstconductive sub-pattern 549 a and the fifth substrate second conductivesub-pattern 549 b in coaxial complimentary alignment with the thirdsubstrate first conductive pattern 536 a and the third substrate secondconductive pattern 536 b, respectively, about axis 107 a and axis 107 b,respectfully.

The fifth substrate first vias 591 are in complimentary alignment withthe third substrate fourth vias 497, the base substrate fourth vias 491,the second substrate fourth vias 496, and the fourth substrate firstvias 588. The fifth substrate second vias 592 are in complimentaryalignment with the third substrate third vias 586, the hub second vias584, the second substrate third vias 585, and the fourth substratesecond vias 583. Complimentary alignment as referred to herein means ina relationship that will affect electrical interconnection and/ormagnetic properties.

It is understood that, in accordance with another embodiment of making ahorizontal array of two or more magnetic devices, the base substrate 502of FIG. 30 may comprise two base substrates 402 of FIG. 29 coupledtogether in side-by-side relationship.

In accordance with the embodiment of FIG. 30, the plated through holesin the base substrate 502, the second substrate first conductive pattern526 a, the second substrate second conductive pattern 526 b, the thirdsubstrate first conductive pattern 536 a, the third substrate secondconductive pattern 536 b, the fourth conductive pattern 547, the fifthconductive pattern 548, and the various vias are electricallyinterconnected to define one or more electric circuits that surround thecores 410, thereby forming a winding-type relationship such asassociated with a winding-type electric circuit that cooperates so as toinduce a magnetic flux within the cores 410 when the one or moreelectric circuits are energized by a voltage source, to produce, by wayof example a transformer configuration. Embodiments of differentwinding-type relationships will be discussed below.

FIG. 31 is a perspective exploded view of a first magnetic device 601 aand a second magnetic device 601 b each in a transformer configurationthat are arrayed vertically in the same assembly along the same axis 107to define a vertical multi-device magnetic component 600 as a verticalmulti-transformer device, in accordance with an embodiment. The firstmagnetic device 601 a and the second magnetic device 601 b aresubstantially the same as the first magnetic device 501 a and the secondmagnetic device 501 b, respectively, of FIG. 30. In this implementation,two cores (not shown), one in the first base substrate 602 a and asecond in the second base substrate 602 b, are in vertical alignment toeach another, in a vertical integration defining a vertical array. Thetransformer primary windings are implemented by each of a first secondsubstrate 622 a and a first third substrate 632 a, and a second secondsubstrate 622 b and a second third substrate 632 b, respectively, withthe respective plated through holes in the first base substrate 602 aand second base substrate 602 b, respectively. The transformer secondarywindings are implemented by a first fourth substrate 642 a and a firstfifth substrate 652 a, and a second fourth substrate 642 b and a secondfifth substrate 652 b, respectively, with the respective plated throughholes in the first base substrate 602 a and second base substrate 602 b,respectively.

The circuit design on the first second substrate 622 a, second secondsubstrate 622 b, first third substrate 632 a, second third substrate 632b, first fourth substrate 642 a, second fourth substrate 642 b, firstfifth substrate 652 a, and the second fifth substrate 652 b, determineswhether the windings are connected in either a series, parallel, orcombination of series and parallel configuration.

Since the first magnetic device 601 a and the second magnetic device 601b are substantially the same as the first magnetic device 501 a and thesecond magnetic device 501 b, respectively, of FIG. 30, specific detailsof the various components have already been presented with theembodiment of FIG. 30. The first magnetic device 601 a comprises a firstbase substrate 602 a, a first second substrate 622 a, a first thirdsubstrate 632 a, a first fourth substrate 642 a, and a first fifthsubstrate 652 a. The first base substrate 602 a substantiallycorresponds to the base substrate 502 of FIG. 30, but having only onecore cavity 431. The first second substrate 622 a substantiallycorresponds to the second substrate 522 of FIG. 30, but having only thesecond substrate first conductive pattern 526 a. The first thirdsubstrate 632 a substantially corresponds to the third substrate 532 ofFIG. 30, but having only the third substrate first conductive pattern536 a. The first fourth substrate 642 a substantially corresponds to thefourth substrate 542 of FIG. 30, but having only the fourth substratefirst conductive pattern 541 a. The first fifth substrate 652 asubstantially corresponds to the fifth substrate 552 of FIG. 30, buthaving only the fifth substrate first conductive sub-pattern 549 a.

The second magnetic device 601 b comprises a second base substrate 602b, a second second substrate 622 b, a second third substrate 632 b, asecond fourth substrate 642 b, and a second fifth substrate 652 b. Thesecond base substrate 602 b substantially corresponds to the basesubstrate 502 of FIG. 30, but having only one core cavity 431. Thesecond second substrate 622 b substantially corresponds to the secondsubstrate 522 of FIG. 30, but having only the second substrate secondconductive pattern 526 b. The second third substrate 632 b substantiallycorresponds to the third substrate 532 of FIG. 30, but having only thethird substrate second conductive pattern 536 b. The second fourthsubstrate 642 b substantially corresponds to the fourth substrate 542 ofFIG. 30, but having only the fourth substrate second conductivesub-pattern 541 b. The second fifth substrate 652 b substantiallycorresponds to the fifth substrate 552 of FIG. 30, but having only thefifth substrate second conductive sub-pattern 549 b.

The various vias and plated through holes of the first magnetic device601 a and a second magnetic device 601 b as substantially similar asthose for the first magnetic device 501 a and the second magnetic device501 b, respectively, of FIG. 30, so is not repeated here. It isunderstood that various vias and plated through holes may affectelectrical communication within each of the first magnetic device 601 aand the second magnetic device 601 b and between the first magneticdevice 601 a and the second magnetic device 601 b.

The first base substrate 602 a, the first second substrate 622 a, andthe first third substrate 632 a is shown in FIG. 31 as assembled. Thesecond base substrate 602 b, the second second substrate 622 b, and thesecond third substrate 632 b is also shown in FIG. 31 as assembled. Thefirst fourth substrate 642 a, second fourth substrate 642 b, first fifthsubstrate 652 a, and the second fifth substrate 652 b are shown in anexploded view.

The first second substrate 622 a comprises a first second substratesecond surface 624 a including a first second substrate conductivepattern 626 a disposed thereon. The first fourth substrate 642 acomprises a first fourth substrate second surface 644 a including afirst fourth substrate conductive pattern 646 a disposed thereon, and afirst fourth substrate first surface 645 a. The first third substrate632 a comprises a first third substrate second surface 634 a including afirst third substrate conductive pattern 636 a disposed thereon. Thefirst fifth substrate 652 a comprises a first fifth substrate secondsurface 654 a including a first fifth substrate conductive pattern 656 adisposed thereon.

The second second substrate 622 b comprises a second second substratesecond surface 624 b including a second second substrate conductivepattern 626 b disposed thereon. The second fourth substrate 642 bcomprises a second fourth substrate second surface 644 b including asecond fourth substrate conductive pattern 646 b disposed thereon, and asecond fourth substrate first surface 645 b. The second third substrate632 b comprises a second third substrate second surface 634 b includinga second third substrate conductive pattern 636 b disposed thereon. Thesecond fifth substrate 652 b comprises a second fifth substrate secondsurface 654 b including a second fifth substrate conductive pattern 656b disposed thereon.

Respective electrical traces are operable to interconnect the firsttransformer embedded magnetic device 601 a and the second transformerembedded magnetic device 601 b in electrical communication defining anembedded magnetic component 600 as a vertical multi-transformer device.Via interconnects at respective input/output pads connect the primaryand secondary windings of the first magnetic device 601 a and the secondmagnetic device 601 b in either a series or parallel configuration,suitable for a particular purpose.

To manage parameters like winding inductance, impedance, resistance andpower dissipation, it is useful to array two or more transformers orinductors in either a series or parallel configuration. The embodimentspresented herein may be used to manage such parameters, among others.

FIG. 32 depicts a schematic diagram of a multi-device embedded magneticcomponent 700 including a first transformer 701 a and a secondtransformer 701 b that are vertically arrayed, in accordance with anembodiment. The first primary winding 703 a and the second primarywinding 703 b are electrically connected in series and the firstsecondary winding 704 a and the second secondary winding 704 b areelectrically connected in parallel.

This embodiment may be useful for switch mode power converters (SMPC),where the voltage is stepped-down from primary to secondary windings andthe current is stepped-up from the primary to secondary windings. ForSMPC applications, the primary inductance is large enough to support theinput switching voltage, according to the relation V=L di/dt. Also, thenumber of windings on the primary side is large enough to prevent theferromagnetic core from reaching saturation. In conventional wire-wounddevices and embedded magnetics, the core structure limits the number ofwindings. In accordance with embodiments herein, the primary winding oftwo or more transformers may be connected in series to achieve arequired number of windings and inductance. In conventional wire-wounddevices, the secondary side of the transformer delivers current to theload. In accordance with embodiments herein, the secondary windings areconnected in parallel to minimize power dissipation in the windings dueto the AC impedance and winding.

In connecting the windings of two transformers in series and parallel,the designer must scale the winding ratios accordingly. The windingratio N, is defined as the ratio of the number of turns in the primarywinding Np divided by the windings on the secondary winding, Ns.Windings in series are added to get the aggregate number of turns in thewinding. The aggregate number of turns for parallel windings isdetermined by adding the inverse of each winding and then taking theinverse of the sum. For example, the winding ratio of M number oftransformers connected in a series and parallel configuration, one canuse the relationship:N=Np/Ns=(N _(p1) +N _(p2) + . . . N _(pM))/(1/N _(s1)+1/N _(s2)+1/N_(sM))⁻¹

Similarly, the aggregate winding inductance can be determined by summingthe inductance of devices connected in series and taking the inverse ofthe inverse sum of devices connected in parallel.

FIGS. 33A-33D depicts printed circuit board artwork for a multi-deviceembedded magnetic component 700 as a device substantially similar to theembedded magnetic component 600 of FIG. 31 comprising two stacked, invertical alignment, embedded magnetic transformers in the form of afirst transformer 701 a and a second transformer 701 b which areconnected in a series and parallel configuration, in accordance with theschematic of FIG. 32. Each embedded magnetic device is implemented on aseparate base substrate: first base substrate 602 a and second basesubstrate 602 b, respectively, of FIG. 31. Each embedded magnetic deviceis implemented with 4 circuit layers, with the primary winding on innerlayers, first layer and second layer, and the secondary winding on outerlayers, third layer and fourth layer.

FIG. 33A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the first transformer 701 a, such as shown for first magneticdevice 601 a of FIG. 31. The first layer first primary winding is in theform of the first second substrate conductive pattern 726 a which isdisposed on the first second substrate 722 a defining the first layer.The second layer first primary winding is in the form of a first thirdsubstrate conductive pattern 736 a which is disposed on the first thirdsubstrate 732 a defining the second layer. The first primary winding ofthe first transformer 701 a, which surrounds core 410, comprisessubstantially of the first second substrate conductive pattern 726 a andthe first third substrate conductive pattern 736 a.

FIG. 33B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the second transformer 701 b, such as shown for secondmagnetic device 601 b of FIG. 31. The first layer second primary windingis in the form of the second second substrate conductive pattern 726 bwhich is disposed on the second second substrate 722 b defining thefirst layer. The second layer second primary winding is in the form ofthe second third substrate conductive pattern 736 b which is disposed onthe second third substrate 732 b defining the second layer. The secondprimary winding of the second transformer 701 b, which surrounds core410, comprises substantially of the second second substrate conductivepattern 726 b and the second third substrate conductive pattern 736 b.

FIG. 33C illustrates printed circuit board artwork of a third layerfirst secondary winding superimposed on a fourth layer first secondarywinding of the first transformer 701 a, such as shown for first magneticdevice 601 a of FIG. 31. The third layer first secondary winding is inthe form of the first fourth conductive pattern 746 a which is disposedon the first fourth substrate 742 a defining the third layer. The fourthlayer first secondary winding is in the form of the first fifthsubstrate conductive pattern 756 a which is disposed on the first fifthsubstrate 752 a defining the fourth layer. The first secondary windingof the first transformer 701 a comprises substantially of the firstfourth conductive pattern 746 a and the first fifth substrate conductivepattern 756 a.

FIG. 33D illustrates printed circuit board artwork of a third layersecond secondary winding superimposed on a fourth layer second secondarywinding of the second transformer 701 b. The third layer secondsecondary winding is in the form of the second fourth conductive pattern746 b which is disposed on the second fourth substrate 742 b definingthe third layer. The fourth layer second secondary winding is in theform of the second fifth substrate conductive pattern 756 b which isdisposed on the second fifth substrate 752 b defining the fourth layer.The second secondary winding of the second transformer 701 b comprisessubstantially of the second fourth conductive pattern 746 b and thesecond fifth substrate conductive pattern 756 b.

Connection nodes are identified with the letters A through F. In FIGS.33A-33D, the primary winding starts is at node A and its polarity isnoted by the dot in the schematic symbol. Nodes C and B connect inseries and the primary winding finishes at node D. The secondary windingstarts at node E and finishes is at node F. Although the embodiment ofFIGS. 33A-33D comprises two arrayed transformers, it is appreciated thata larger number of transformers may be vertically stacked and arrayed,as required by the application or purpose of the device.

FIG. 34 depicts a schematic diagram of a magnetic component 800, in theform of a power transformer, including a first transformer 801 a and asecond transformer 801 b that are horizontally arrayed, in accordancewith an embodiment. The first primary winding 803 a and the secondprimary winding 803 b are electrically connected in series and the firstsecondary winding 804 a and the second secondary winding 804 b areelectrically connected in parallel.

FIGS. 35A-35B depicts printed circuit board artwork for a magneticcomponent substantially similar to the horizontal multi-device embeddedmagnetic component 500 of FIG. 30 comprising two embedded magnetictransformers in the form of a first transformer 801 a and a secondtransformer 801 b, which are connected in a series and parallelconfiguration, in accordance with the schematic of FIG. 34. The firsttransformer 801 a and the second transformer 801 b are in a side-by-siderelationship, sharing a same base substrate 502 of FIG. 30, sharing asame second substrate 822 and sharing a same third substrate 832, andwith a core 410 disposed in each core cavity 431 defined by the basesubstrate 502 of FIG. 30. The horizontal multi-transformer embeddedmagnetic component 800 further comprises a fourth substrate 842, and afifth substrate 852, each operable to interconnect the first transformer801 a and the second transformer 801 b in electrical communication,defining a horizontal multi-transformer embedded magnetic component 800.

The transformer first layer primary windings are implemented by thesecond substrate 822 and the second layer primary windings areimplemented by the third substrate 832. The transformer first layersecondary windings are implemented by a fourth substrate 842 and thesecond layer secondary windings are implemented by a fifth substrate852. The circuit design on the second substrate 822 and the thirdsubstrate 832 and the fourth substrate 842 and the fifth substrate 852determines whether the windings are connected in either a series,parallel, or combination of series and parallel configuration.

FIG. 35A illustrates printed circuit board artwork of a first layerprimary winding superimposed on a second layer primary winding of thefirst transformer 801 a and the second transformer 801 b. The firstlayer primary winding is in the form of the second substrate firstconductive pattern 826 a and the second substrate second conductivepattern 826 b which are disposed on the second substrate 822 definingthe first layer. The second layer primary winding is in the form of thesecond substrate first conductive pattern 836 a and the second substratesecond conductive pattern 836 b which are disposed on the thirdsubstrate 832 defining the second layer.

FIG. 35B illustrates printed circuit board artwork of a third layersecondary winding superimposed on a fourth layer secondary winding ofthe first transformer 801 a and the second transformer 801 b. The thirdlayer secondary winding is in the form of the fourth conductive pattern847 which is disposed on the fourth substrate 842 defining the thirdlayer. The fourth layer secondary winding is in the form of the fifthconductive pattern 848 which is disposed on the fifth substrate 852defining the fourth layer.

Referring to FIGS. 34 and 35A, 35B, the transformer primary windings areconnected in series, with the start at node A and the finish at node B.The secondary windings are connected in parallel to minimize the windingimpedance. The start begins at node E and the winding finish is at nodeF. The embodiment shown in FIGS. 35A and 35B depicts two transformers inthe array. It is appreciated that a larger number of transformers may bearrayed in the horizontal configuration, as required by the applicationand purpose.

FIGS. 36 and 37A-37D shows a configuration that is useful for powerconverter applications, in accordance with an embodiment. It is oftenuseful to have multiple voltage outputs in a circuit. In the schematicdiagram of FIG. 36, a magnetic component 900 comprising twotransformers, a first transformer 901 a and a second transformer 901 b,are arrayed with the primary windings 903 a, 903 b connected in series.The secondary windings 904 a, 904 b are separate. The turns ratio, N,between the primary and secondary windings can be different, asindicated by N1 and N2. FIGS. 37A-37D provides an embodiment of thewinding artwork for a stacked configuration of the schematic of FIG. 36.

The artwork in FIGS. 37A-37D is substantially similar to the embodimentof FIGS. 33A-33C. However, in this configuration the secondary windingsare split and not connected in parallel. FIG. 37D also depicts adifferent number of secondary windings for the first transformer 901 aand second transformer embedded magnetic device 901 b as compared withthe embodiment of FIG. 33D.

FIG. 37A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the first transformer 901 a, such as shown for first magneticdevice 601 a of FIG. 31. The first layer first primary winding is in theform of the first second substrate conductive pattern 926 a which isdisposed on the first second substrate 922 a defining the first layer.The second layer first primary winding is in the form of a first thirdsubstrate conductive pattern 936 a which is disposed on the first thirdsubstrate 932 a defining the second layer. The first primary winding ofthe first embedded magnetic device as a first transformer 901 a, whichsurrounds core 410, comprises substantially of the first secondsubstrate conductive pattern 726 a and the first third substrateconductive pattern 936 a.

FIG. 37B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the second transformer 901 b, such as shown for secondmagnetic device 601 b of FIG. 31. The first layer second primary windingis in the form of the second second substrate conductive pattern 926 bwhich is disposed on the second second substrate 922 b defining thefirst layer. The second layer second primary winding is in the form ofthe second third substrate conductive pattern 936 b which is disposed onthe second third substrate 932 b defining the second layer. The secondprimary winding of the second embedded magnetic device as a secondtransformer 901 b, which surrounds core 410, comprises substantially ofthe second second substrate conductive pattern 926 b and the secondthird substrate conductive pattern 936 b.

FIG. 37C illustrates printed circuit board artwork of a third layerfirst secondary winding superimposed on a fourth layer first secondarywinding of the first embedded magnetic device as a first transformer 901a, such as shown for first magnetic device 601 a of FIG. 31. The thirdlayer first secondary winding is in the form of the first fourthconductive pattern 946 a which is disposed on the first fourth substrate942 a defining the third layer. The fourth layer first secondary windingis in the form of the first fifth substrate conductive pattern 956 awhich is disposed on the first fifth substrate 954 a defining the fourthlayer. The first secondary winding of the first embedded magnetic deviceas a first transformer 901 a comprises substantially of the first fourthconductive pattern 946 a and the first fifth substrate conductivepattern 956 a.

FIG. 37D illustrates printed circuit board artwork of a third layersecond secondary winding superimposed on a fourth layer second secondarywinding of the second transformer 901 b, such as shown for secondmagnetic device 601 b of FIG. 31. The third layer second secondarywinding is in the form of the second fourth conductive pattern 946 bwhich is disposed on the second fourth substrate 942 b defining thethird layer. The fourth layer second secondary winding is in the form ofthe second fifth substrate conductive pattern 956 b which is disposed onthe second fifth substrate 954 b defining the fourth layer. The secondsecondary winding of the second embedded magnetic device as a secondtransformer 901 b comprises substantially of the second fourthconductive pattern 946 b and the second fifth substrate conductivepattern 956 b.

The artwork in FIG. 37C depicts that the first secondary winding hasfour winding turns for the first transformer 901 a and that the secondsecondary winding has six winding turns for the second transformer 901 bin FIG. 37D. It is appreciated that a different number of turns andwinding ratios may be implement on each transformer embedded magneticdevice in accordance with design needs. Also, it is appreciated to arraymore transformer embedded magnetic devices in the vertical stack, asrequired by the application. Transformers can also be arrayed in acombination of horizontal and vertical configurations to meet theperformance goals of the application.

In both power and communication circuits, for example, it is oftenuseful to have a transformer connected in series with either a filterinductor or a common mode inductor. A common mode inductor consists oftwo or more conductive windings on a ferromagnetic core. The common modeinductor is commonly referred to as a common mode “choke” and is usedfor filtering common mode signals. The common mode inductor provides ahigh impedance to common mode signals and low impedance to differentialmode signals.

FIG. 38 depicts a schematic diagram of a transformer-choke magneticcomponent 1000, in the form of a series connection of a transformerembedded magnetic device 1001 and a common mode inductor 1105, inaccordance with an embodiment.

FIGS. 39A-39D depicts printed circuit board artwork for thetransformer-choke magnetic component 1000 of FIG. 38 comprising atransformer embedded magnetic device 1001 and the common mode inductor1005 connected in a stacked, vertical alignment, in accordance with theschematic of FIG. 38, in accordance with an embodiment. Each embeddedmagnetic device is implemented on a separate base substrate: first basesubstrate 1022 a and second base substrate 1022 b, respectively. Eachembedded magnetic device is implemented with 4 circuit layers, with theprimary windings 1003, 1004 on inner layers, first layer and secondlayer, and the secondary windings 1013, 1014 on outer layers, thirdlayer and fourth layer, of the respective devices. Only the primarywindings will be further discussed as the implementation of thesecondary windings will be understood from the previous embodiments.

FIG. 39A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the transformer embedded magnetic device 1001, such as shownfor first magnetic device 601 a of FIG. 31. The first layer firstprimary winding is in the form of the first second substrate conductivepattern 1026 which is disposed on the first second substrate 1022 adefining the first layer. The second layer first primary winding is inthe form of a first third substrate conductive pattern 1036 which isdisposed on the first third substrate 1032 a defining the second layer.The first primary winding of the transformer embedded magnetic device1001, which surrounds core 410, comprises substantially of the firstsecond substrate conductive pattern 1026 and the first third substrateconductive pattern 1036.

FIG. 39B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the common mode inductor 1105, in accordance with anembodiment. The first layer second primary winding is in the form of thesecond second substrate conductive pattern 1046 which is disposed on thesecond second substrate 1022 b defining the first layer. The secondlayer second primary winding is in the form of the second thirdsubstrate conductive pattern 1056 which is disposed on the second thirdsubstrate 1032 b defining the second layer. The second primary windingof the common mode inductor 1105, which surrounds core 410, comprisessubstantially of the second second substrate conductive pattern 1046 andthe second third substrate conductive pattern 1056.

Node A is the start of the first primary windings of the transformerembedded magnetic device 1001 and node B is the finish. On the secondaryside, nodes C and D join the transformer embedded magnetic device 1001and the common mode inductor 1005. Node C has the same polarity as nodeA, and node D has the same polarity as Node B. On the common modeinductor 1005, the windings at node C and D both start on the same firstlayer and finish on the same second layer. The output at node E is thesame polarity as node A and the output at node F is the same polarity asnode B.

FIG. 40 depicts a schematic diagram of a two-choke magnetic component1100, in the form of a series connection of a first common mode inductor1101 and a second common mode inductor 1105, in accordance with anembodiment. This configuration is useful to implement a higher number ofwindings and consequently a higher common mode inductance.

FIGS. 41A-41D depicts printed circuit board artwork for the two-chokemagnetic component 1100 of FIG. 40 comprising a first common modeinductor 1101 and the second common mode inductor 1105 connected in astacked, vertical alignment, in accordance with the schematic of FIG.40, in accordance with an embodiment. Each embedded magnetic device isimplemented on a separate base substrate: first base substrate 1122 aand second base substrate 1122 b, respectively. Each embedded magneticdevice is implemented with 4 circuit layers, with a first primarywinding 1103 and a second primary winding 1112 on inner layers, firstlayer and second layer, and the first secondary winding 1114 and secondsecondary winding 1113 on outer layers, third layer and fourth layer, ofthe respective devices. Only the primary windings will be furtherdiscussed as the implementation of the secondary windings will beunderstood from the previous embodiments.

FIG. 41A illustrates printed circuit board artwork of a first layerfirst primary winding 1103 superimposed on a second layer first primarywinding 1112 of the first common mode inductor 1101. The first layerfirst primary winding 1103 is in the form of the first second substrateconductive pattern 1126 which is disposed on the first second substrate1122 defining the first layer. The second layer first primary winding isin the form of a first third substrate conductive pattern 1136 which isdisposed on the first third substrate 1132 a defining the second layer.The first primary winding of the first common mode inductor 1101, whichsurrounds the core 410, comprises substantially of the first secondsubstrate conductive pattern 1126 and the first third substrateconductive pattern 1136.

FIG. 41B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the common mode inductor 1105, in accordance with anembodiment. The first layer second primary winding is in the form of thesecond second substrate conductive pattern 1146 which is disposed on thesecond second substrate 1122 b defining the first layer. The secondlayer second primary winding is in the form of the second thirdsubstrate conductive pattern 1156 which is disposed on the second thirdsubstrate 1132 b defining the second layer. The second primary windingof the common mode inductor 1105, which surrounds the core 410,comprises substantially of the second second substrate conductivepattern 1146 and the second third substrate conductive pattern 1156.

Implementing two embedded magnetic inductors or common mode inductors inseries in the horizontal configuration may use the methods presented forearlier embodiments. In the vertical configuration, the designer musttake care to on which layers the windings start and finish, assuring theright polarity on the inductors. Referring again to FIGS. 41Aa and 41B,for the first common mode inductor 1101, the start windings (nodes A andD) are implemented on the first layer and the finish windings areimplemented on the second layer. On the second common mode inductor1105, the start windings (B and E) are implemented on the first layerand the finish windings (C and F) are implemented on the second layer.While the embodiment shows two devices in series, it is appreciated thata larger number of devices may be arrayed as required by theapplication.

There are a variety of ferromagnetic materials that can be used for thecores of the embedded magnetic devices. Each has different permeability,frequency response and loss characteristics. It is appreciated thatinductors comprising different magnetic materials may be used, forexample, but not limited to, to extend the frequency of operation and toemphasize impedance (attenuation) within a specific frequency band.Also, the inductors may be implemented with shunt or parallel capacitorsto implement filter circuits. Having access to the intermediate nodes, Band E in FIG. 40, provides a connection point for adding shunt andparallel capacitors and enhancing the filtering properties of thecircuit, in accordance with embodiments.

In another embodiments common mode inductors are implemented in serieswith differential mode inductors. FIG. 42 depicts a schematic diagram ofa magnetic component 1200 comprising a 2-wire common mode inductor 1201in series with a 2-wire differential mode inductor 1204, in accordancewith an embodiment. The dots in the schematic identify the windingpolarity. In this embodiment, the polarity of the second winding in thedifferential mode inductor 1204 opposes the polarity in the winding ofthe common mode inductor 1201. Each embedded magnetic device isimplemented with 4 circuit layers, with a first primary winding 1203 anda second primary winding 1212 on inner layers, first layer and secondlayer, and the first secondary winding 1214 and second secondary winding1213 on outer layers, third layer and fourth layer, of the respectivedevices. Only the primary windings will be further discussed as theimplementation of the secondary windings will be understood from theprevious embodiments.

Implementing a common mode inductor 1201 and differential mode inductor1204 in series in a horizontal configuration may use the methodspresented for earlier embodiments. In the vertical stackedconfiguration, the designer must take care on which layers the windingsstart and finish.

FIGS. 43A and 43B is artwork for a stacked common mode inductor 1201 anddifferential mode inductor 1204 in accordance with an embodiment. On thecommon mode inductor 1201 the start windings (nodes A and D) areimplemented on the first layer and the finish windings are implementedon the second layer. On the differential mode inductor 1204 the startwinding at node B is implemented on the first layer and the finishwinding at node E is implemented on the second layer. The correspondingfinish winding at node E is implemented on the second layer and thestart winding at node F is implemented on first layer. While theembodiment shows two devices in series, it is appreciated that moredevices can be arrayed as required by the application.

FIGS. 43A and 43B depicts printed circuit board artwork for the 2-wirecommon mode inductor 1201 and a 2-wire differential mode inductor 1204connected in a stacked, vertical alignment, in accordance with theschematic of FIG. 42, in accordance with an embodiment. Each embeddedmagnetic device is implemented on a separate base substrate: first basesubstrate 1222 a and second base substrate 1222 b, respectively. Eachembedded magnetic device is implemented with 4 circuit layers, with theprimary winding on inner layers, first layer and second layer, and thesecondary windings on outer layers, third layer and fourth layer, of therespective devices. Only the primary windings will be further discussedas the implementation of the secondary windings will be understood fromthe previous embodiments.

FIG. 43A illustrates printed circuit board artwork of a first layerfirst primary winding superimposed on a second layer first primarywinding of the 2-wire common mode inductor 1201. The first layer firstprimary winding is in the form of the first second substrate conductivepattern 1226 which is disposed on the first second substrate 1222 adefining the first layer. The second layer first primary winding is inthe form of a first third substrate conductive pattern 1236 which isdisposed on the first third substrate 1232 a defining the second layer.The first primary winding of the 2-wire common mode inductor 1201, whichsurrounds the core 410, comprises substantially of the first secondsubstrate conductive pattern 1226 and the first third substrateconductive pattern 1236.

FIG. 43B illustrates printed circuit board artwork of a first layersecond primary winding superimposed on a second layer second primarywinding of the 2-wire differential mode inductor 1204, in accordancewith an embodiment. The first layer second primary winding is in theform of the second second substrate conductive pattern 1246 which isdisposed on the second second substrate 1222 b defining the first layer.The second layer second primary winding is in the form of the secondthird substrate conductive pattern 1257 which is disposed on the secondthird substrate 1232 b defining the second layer. The second primarywinding of the 2-wire differential mode inductor 1204, which surroundsthe core 410, comprises substantially of the second second substrateconductive pattern 1246 and the second third substrate conductivepattern 1257.

Capacitive coupling between the conductors of the primary conduit mayinduce noise coupling. Electromagnetic energy can also emanate from theferromagnetic core and stimulate other cores and windings in the array.In addition to coupling signal noise, capacitive coupling can also causecircuit imbalance and limit the device's useful frequency bandwidth.Ground shielding may be added around an embedded magnetic device toreduce coupled noise between the winding conductors, in accordance withembodiments.

In power circuits, shielding may be used to provide heat conduction andhelp spread heat away from the embedded magnetic device.

On a single base substrate, such as presented in FIG. 30, groundshielding can be implemented between two arrayed devices by filling theregions between the two devices with conductive copper, in accordancewith an embodiment. Grounded vias can be arrayed between two devices toprovide shielding singularly or in combination with the shieldingpresented above.

When two embedded magnetic devices are stacked, such as presented inFIG. 31, coupling may occur between the conductive windings on thevarious layers. Capacitive and inductive coupling diminishes withdistance and can be managed to some degree by separating the stackarrayed devices with an insulation layer, such as one comprisingpolyimide, among others. There may be constraints on the device height,however, which may limit the thickness of the separation layer. Due totheir close proximity, inner layer windings will exhibit the greatestamount of capacitive coupling. An insulation layer with low dielectricconstant to minimize capacitive coupling may be added to the assembly.

In accordance with an embodiment, a conductive layer is placed betweentwo stacked devices and connected to electrical ground during the deviceoperation, to implement a ground shield there between. This will isolatethe two substrates from coupled noise, and will also provide thegreatest amount of capacitive loading and imbalance on the conductivewindings.

In accordance with another embodiment, the ground shield comprises across-hatch screen pattern rather than a solid conductive layer. Thecross-hatch screen can provide an effective shield while reducing thecapacitance between the winding conductors. The cross-hatch screen willprovide capacitive loading and create imbalance, yet to a lower degreethan the solid conductive shield. To further minimize capacitivecoupling and imbalance, conductive fingers on the ground shield layercan be arrayed either between the inner layer winding conductors orimplemented as thin conductors positioned between the winding conductorson interfacing layers, among others, in accordance with embodiments.

FIG. 44 is a cross sectional view of a magnetic component 960 comprisingtwo stacked magnetic components, first embedded magnetic component 961 aand second embedded magnetic component 961 b, with a ground shieldinglayer 965 there between, in accordance with an embodiment. The firstembedded magnetic component 961 a and second embedded magnetic component961 b may be represented by the first magnetic device 601 a and a secondmagnetic device 601 b coupled in vertical alignment of FIG. 31. A groundshielding layer 965 is disposed between the first embedded magneticcomponent 961 a and second embedded magnetic component 961 b, placingthe ground shielding layer 965 adjacent to the first fifth substrateconductive pattern 656 a and second fourth substrate conductive pattern646 b, respectively.

The ground shielding layer 965 comprises a ground shield conductivepattern 967 and dielectric layer 969. Schematic symbols representing thecoupling capacitance CP between the first fifth substrate conductivepattern 656 a and second fourth substrate conductive pattern 646 b andthe ground shield conductive pattern 967 are shown in the crosssectional view. The ground shielding layer 965 can be implemented with alow dielectric material. PCB processes may use FR-4 fiberglass orpolyimide material, but is not limited thereto. The cross section showsground shield conductive pattern 967 placed substantially mid-waybetween the individual conductive traces of the first fifth substrateconductive pattern 656 a and second fourth substrate conductive pattern646 b. In the horizontal direction, the ground shield conductive pattern967 is staggered between the individual conductive traces of the firstfifth substrate conductive pattern 656 a and second fourth substrateconductive pattern 646 b to minimize overlap and capacitive coupling.

FIG. 45 depicts a section of the circuit artwork for the first fifthsubstrate conductive pattern 656 a showing the individual fifthconductive traces 638 implemented on the first fifth substrate 652 a, asshown in FIG. 31, by way of example. The first fifth substrateconductive pattern 656 a is superimposed on the ground shield conductivepattern 967 implemented on another layer, in accordance with anembodiment. The ground shield conductive pattern 967 defines shieldfingers 968 placed between the individual fifth conductive traces 638.The shield fingers 968 are not connected at the center of the firstfifth substrate conductive pattern 656 a to avoid creating ground-loops.It is understood that there is a trade-off between the amount ofshielding and capacitive loading. The shield fingers 968 can be shapedto balance capacitive coupling and the amount of shielding.

FIG. 46 is a cross sectional view of a magnetic component 970 comprisingtwo stacked magnetic components, first embedded magnetic component 961 aand second embedded magnetic component 961 b, with a ground shieldinglayer 975 there between, in accordance with an embodiment. The firstembedded magnetic component 961 a and second embedded magnetic component961 b may be represented by the first magnetic device 601 a and a secondmagnetic device 601 b coupled in vertical alignment of FIG. 31. A groundshielding layer 975 is disposed between the first embedded magneticcomponent 961 a and second embedded magnetic component 961 b, placingthe ground shielding layer 975 adjacent to the first fifth substrateconductive pattern 656 a and second fourth substrate conductive pattern646 b, respectively.

The ground shielding layer 975 comprises a ground shield conductivepattern 977 and dielectric layer 969. Schematic symbols representing thecoupling capacitance CP between the first fifth substrate conductivepattern 656 a and second fourth substrate conductive pattern 646 b andthe ground shield conductive pattern 967 are shown in the crosssectional view. The ground shielding layer 975 can be implemented with alow dielectric material. PCB processes may use FR-4 fiberglass orpolyimide material, but is not limited thereto. The cross section showsground shield conductive pattern 977 placed substantially mid-waybetween the individual conductive traces of the first fifth substrateconductive pattern 656 a and second fourth substrate conductive pattern646 b. In the horizontal direction, the ground shield conductive pattern967 is directly between the individual fifth conductive traces 638 ofthe first fifth substrate conductive pattern 656 a and second fourthsubstrate conductive pattern 646 b to minimize overlap and capacitivecoupling.

FIG. 47 depicts a section of the circuit artwork for the first fifthsubstrate conductive pattern 656 a showing the individual fifthconductive traces 638 implemented on the first fifth substrate 652 a, asshown in FIG. 31, by way of example.

The first fifth substrate conductive pattern 656 a is superimposed onthe ground shield conductive pattern 967 implemented on another layer,in accordance with an embodiment. The ground shield conductive pattern977 defines shield fingers 978 placed between the individual fifthconductive traces 638 and the second fourth substrate conductive pattern646 b, so as to at least partially overlap the individual fifthconductive traces 638. The shield fingers 978 are not connected at thecenter of the first fifth substrate conductive pattern 656 a to avoidcreating ground-loops. It is understood that there is a trade-offbetween the amount of shielding and capacitive loading. The shieldfingers 978 can be shaped to balance capacitive coupling and the amountof shielding.

The shield fingers 978 are substantially thinner than the individualfifth conductive traces 638 of the first fifth substrate conductivepattern 656 a and second fourth substrate conductive pattern 646 b. Theshield fingers 978 capture electromagnetic energy that may pass betweenthe individual fifth conductive traces 638 of the first fifth substrateconductive pattern 656 a and second fourth substrate conductive pattern646 b. The designer has to balance the coupling capacitance, circuitimbalance and the degree of shielding provided by the shield fingers978. Keeping the shield fingers thin reduces imbalance as compared witha wider shield finger, yet allows some electromagnetic energy to passbetween the individual fifth conductive traces 638 of the first fifthsubstrate conductive pattern 656 a and second fourth substrateconductive pattern 646 b.

Example Embodiments of Embedded High Voltage Transformer Components andMethods

Transformers are commonly used on electronics systems to provide voltageisolation. This is to protect humans and electrical equipment fromvoltage surges and spikes that may occur in and electronic system.Typically, consumer electronics and telecommunications systems require avoltage isolation of 1500 Vrms. The levels are dictated by regionalsafety standards. Medical and industrial equipment often uses very highvoltages and require up to 5000 Vrms isolation between the equipment anduser interface. The advent of wide band gap transistors is pushingvoltage isolation requirements even higher. Integrated Gate BipolarTransistors and (IGBT) and Silicon Carbide MOSFET (SIC) are able tooperate with drain-source voltages exceeding 12 kV. Gate drivetransformers are used to isolate the control circuitry from these highvoltages while driving the transistor gate. These devices are pushingthe voltage isolation requirements from 5 kV to 10 kV and higher.

The voltage isolation is established between the primary and secondarywindings of a transformer and meeting these requirements challenges thedesign and construction. Most transformers are fabricated by windingwire around a ferromagnetic core. A transformer typically has one ormore primary winding and one or more secondary windings. To achieve highvoltage isolation with the conventional construction, the designer mustuse wire with heavy insulation and/or segment the windings with a highisolation barrier material. Polyimide tape and plastic partitions aretypically are used to separate the primary and secondary windings in apower transformer. These add extra steps, complexity and size to theconstruction. Heavy insulation also increase the size of the device andcan be difficult to wind due to its rigidity. It is also difficult tostrip the insulation and expose the wire ends so that they may besoldered or fastened to the input and output (I/O) terminals on thedevice package.

Exposed conductors around the wire terminations can also be a problem.When under high voltage stress, the air around the exposed conductorswill ionize. While the terminals may be spaced sufficiently apart forvoltage isolation, the ionized air can bypass any plastic barriers orinsulating tape and form a cloud around the insulated transformerwindings. Breakdown will occur at weak spots in the wire insulation. Itis important to have sufficient insulation around the windings as wellas separation and barriers between the exposed terminals. Meetingvoltage isolation requirements often requires that the whole transformerpackage be encapsulated in a potting epoxy, which further increases sizeand adds process cost and can limit heat dissipation.

There are a variety of materials that can be used to insulate wire.Common insulators are paper, lacquer, nylon, Polyvinyl Chloride (PVC)and a variety of other polymer materials. High voltage “reinforced” wirewill one or more of these materials to meet isolation requirements.Polymer materials often provide voltage isolation exceeding 12 kV/mm(300 V/mil). Typical magnetic wire may have 0.025-0.05 mm (1 or 2 mils)of insulation whereas “reinforced” wire will have multiple layercoatings and/or much thicker coatings. This often makes the wire rigidand difficult to wind around the magnetic core.

The laminate materials used to fabricate printed circuit boards (PCBs)are generally based on polymers and provide high voltage isolation thatmatches or exceeds what is available on reinforced wire. Embeddedmagnetics (EM) and planar magnetics (PM) both provides alternative tothe traditional construction of winding wire around a ferromagneticcore. Both use PCB construction and processes to produce transformers.In providing voltage isolation, both of these constructions have anadvantage in that the conductor spacing is accurately defined byphotolithography and the conductor separation and insulation thicknesscan be managed better than the wire wound construction. Some laminatematerials are distinguished by high breakdown voltages and differentlaminate materials may be used within the PCB layer stack to achievespecific voltage isolation within a specific PCB thickness.

EM transformers are constructed by routing out a cavity in a substrate,embedding a ferromagnetic core into a substrate material andencapsulating the core to hold it in place. One or more copper layersare laminated to both the top and bottom of the substrate. Vias aredrilled and plated to interconnect winding patterns that are imaged andetched on the top and bottom copper layers.

Similarly, planar magnetics can use PCB construction and processes toproduce a transformer. In this case, layers of spiral windings areimplemented on multiple layers within the printed circuit board andferromagnetic elements are clamped to the top and bottom surface torealize the transformer function.

Three techniques are used to control the voltage isolation in PCBtransformers; selection of laminate material, winding separation on eachlayer, and the winding separation between layers. From a materialsstandpoint, PCB laminates provide very good insulation. FR-4 is a widelyused fiberglass laminate that typically provides voltage isolation inthe range of 11.8 KV/mm to 19.8 kV/mm (300 to 500 V per mil). Morerefined version of FR-4 can provide 25 kV/mm (975V/mil) of isolation.Other laminates provide even higher levels of isolation, yet are lesscommon and often cost much more than standard FR-4. Some of high voltagelaminates that provide voltage isolation exceeding 45 kV/mm are: Arlon33n (polyimide), Isola G200 (Bismaleimide/Triazine Epoxy, BT), Isola P96(polyimide), Nelco 5000 (Bismaleimide/Triazine Epoxy, BT) and DupontPyralux (polyimidie film), among others. These materials typically havea cost exceeding 5× the cost of conventional FR-4 laminates and so it isbeneficial mix them with FR-4 laminates and only apply them betweenconductor layers that are subject to high voltage stress. Mixing thelaminate materials helps constrain the cost, rather than simplyfabricating total PCB stack-up with the high cost insulators. Devicesize and thickness is often an issue for modern electronic systems andthe discriminate use of high voltage laminates can also reduce thedistance between conductor layers and help manage the overall devicethickness.

Conductor spacing is another way to control voltage isolation. With bothEM and PM construction, the transformers windings are accurately definedby imaging and etching. This allows for the conductors to be accuratelyand consistently separated by a specific distance. Required separationcan be determined by the material and device voltage requirement. Forinstance, if one wants to achieve 5000 kV isolation using common FR-4material, the conductors should be separated by >0.43 mm apart (0.43mm×11.7 kV/mm=5 kV). The outer surface of PCBs are usually covered witheither a polymer solder mask or polyimide cover-lay. Polymer liquidphoto-imageable solder mask is widely used in the PCB industry and canprovide about 19 kV/mm (500V/mil) of voltage isolation if applied evenlywith no air bubbles. To assure even thickness over the PCB conductorsand no air bubbles, it is necessary to apply, image, and cure two layersof liquid-imaged solder mask. Even though the underlying conductors maybe spaced accurately for a specified voltage isolation, if they are nearan exposed pad of high voltage potential, they may be susceptible tobreakdown due to an ion cloud forming over the PCB during high voltagestress events. The ion cloud effectively shortens the distance betweenthe exposed pad and the conductors under the solder mask. Rather thanthe horizontal distance between conductors, the isolation merely dependson the thickness of the solder mask between the cloud and the underlyingconductors. Higher insulation resistance can be achieved by applying apolyimide film cover-lay over the conductors, instead of solder mask.Products like the Dupon Pyralux film, noted above, have breakdownvoltages exceeding 117 kV/mm (3000 kV/mil). Two mils of polyimidecover-lay will provide isolation exceeding 5 kV. This illustrates howthe circuit density can be improved by implementing high voltagelaminates at the HV stress spots.

Transformers are used to provide voltage isolation in power conversionand communication systems. FIG. 48a is a schematic representation of atransformer and identifies a primary and secondary winding. Voltageisolation is a measure of the amount of voltage the transformer canhandle before the insulation breaks down and arcing occurs between theprimary and secondary windings. FIG. 48b shows a diagram of an embeddedmagnetic transformer that is bifilar wound around a toroid (ring) shapedcore. This is a 2-layer PCB construction, where one winding patternarray is implemented on the bottom layer and a complementary pattern isimplemented on the top layer. Plated-through-hole-vias (PTH)interconnect the top and bottom winding pattern. The primary andsecondary windings are interleaved and in close proximity, particularlyat the center via array. Voltage isolation is dependent on the conductorand via spacing and presents a limitation on the number of windings thatcan be implemented around the core. Higher voltage isolation requiresmore distance between the vias and conductors in the center of thetoroid, so there is a trade-off between the number of windings that maybe implemented and voltage isolation that can be achieved. The number ofwindings determines the inductance of the transformer, which is a keyfactor in the devices electrical performance. FIG. 48c shows a diagramof a sector wound EM transformer. Here the primary and secondarywindings are separated on two halves of the core. The sector windingconfiguration can provide better isolation than the bifilar wounddevice, however, sector wound transformers typically exhibit higherleakage inductance. Leakage inductance is a secondary parameter thatlimits the transformer frequency bandwidth and contributes to switchingloss in power conversion systems.

FIG. 49 is a cross section view of the EM transformer layer stack.Voltage isolation is determined by the selection of laminate materials,separation between the vias and the thickness of the laminates andsubstrate material between the conductors and the ferromagnetic core. Asnoted above, voltage isolation is primarily determined by the materialproperties of the substrate and laminate and the separation between theconductors and vias. A solder mask is typically applied to the top andbottom surfaces of a printed circuit board to provide environmentalprotection and voltage isolation between the conductors.Liquid-image-able solder mask is widely used in PCB fabrication and hasvoltage breakdown capabilities similar to FR-4 laminate. The designerhas to take particular care where conductors run near exposed pads. If ahigh voltage stress is present between the exposed pad and theconductors under the solder-mask, the air above the underlyingconductors can ionize and become highly conductive. The solder mask isonly a few mils thick and may have micro-cracks and micro air-bubbles.So while the transformer windings on the PCB may have been designed withseparation for a specific voltage isolation, the ionization of the airabove the conductors may present a shorter breakdown path. A remedy isto use multiple layers of solder mask, however, additional process stepsare required and there is a practical limitation to the number of layersand thickness that may be applied. An alternative is to apply a highvoltage polyimide film on the top and bottom surfaces. Polyimideprovides 10× more voltage isolation than a similar thickness of liquidimaged solder mask.

Another way to provide voltage isolation, and also accommodate morewindings, is to implement the EM transformer with 4 or more layers.Again, FIG. 50a shows a schematic diagram of a transformer with aprimary and secondary winding. FIG. 50b shows the primary windingsimplemented on layers 2 and 3. FIG. 50c shows the secondary windings onlayers 1 and 4. FIG. 50d shows the composite of the windings. Note thatthe vias on the primary and secondary windings are interleaved. At theouter via array, they are spaced at sufficient distance to achieve therequired voltage isolation. At the inner region there are actually twocircular via arrays. The primary windings are interconnected on onecircular via array and the secondary windings are interconnected on thesecond circular via array. The distance between the two concentricarrays is designed to achieve a specific voltage isolation.

FIG. 51 is a cross section view of a 4 layer EM transformer. The wholetransformer could be fabricated with high voltage laminate materials,like BT and polyimide. However, these materials are relatively expensivecompared to standard FR-4 laminates. On the other hand, a constructionwholly built with FR-4 may require a relatively thick laminate layerbetween winding layers 1 and 2 and winding layers 3 and 4 to achieve adesired voltage isolation. The device height is often a factor in anelectronics assembly and a design based only on FR-4 laminate may beprohibitively thick. By mixing FR-4 substrate with high voltagelaminates, high voltage isolation can be achieved while managing the PCBthickness.

Embedded magnetics often complement semiconductor packaging to producefunctions like power conversion, digital isolation and isolationamplifiers. With semiconductor packaging, it is often beneficial toimplement transformers and inductors on square shaped ferromagneticcores with two window areas. This core shape is often referred to as asquare binocular. This places the EM windings over a wide area of thecore material and provides for higher inductance values within aconfined area. FIG. 52a is a schematic diagram of a transformer with aprimary and secondary winding. FIGS. 52b and 52c show sector and bifilarwindings applied to the square binocular core. The PCB layer stack issimilar to that depicted in FIG. 49. FIG. 53a is an EM transformer thathas 4 conductive layers and a square binocular shaped core, showinglayers 1 and 4, which form the primary winding. FIG. 53c shows thecomposite winding configuration for a 4 layer EM transformer on a squarebinocular core. This diagram depicts a 6:9 winding ratio. FIG. 53 bshows the primary windings implemented on the inner layers 2 and 3. FIG.53a shows the secondary windings implemented on layers 1 and 4. FIG. 54shows the cross section view of the PCB layer stack for the 4 layertransformer implemented on the square binocular core. As was the case inFIG. 51, a high voltage laminate is used to provide voltage isolationbetween the primary and secondary winding layers.

Planar magnetics is another type of construction used to produce PCBtransformers. With the planar construction, spiral conductor patternsare implemented on multiple PCB layers and two ferromagnetic coreelements are clamped to the outer surface of the PCB. The spiral usuallycoils around a center window area, allowing the core to penetrate thePCB. It is critical that the PCB thickness be well controlled so thatthe two core elements can meet and touch. As with the EM transformersdescribed above, a mix of standard FR-4 and high voltage laminatematerial may be used in the PM design to provide high voltage isolationwithin a specific PCB thickness.

FIG. 55a is a schematic diagram of a transformer and identifies aprimary and secondary winding. FIG. 55b is an exploded view of a planarmagnetic transformer and shows two ferromagnetic core elements that cometogether and clamp across a PCB that contains the transformer windings.The primary and secondary windings are implemented in two or morelayers. Here, we will simply consider a 4 layer PCB design where twolayers are allocated for the primary windings and two are for thesecondary winding. FIG. 55c shows spiral conductor patterns on each ofthe 4 layers and then the primary and secondary windings overlapped inthe bottom cells. As indicated above, more winding layers can beimplemented to achieve a specific primary inductance and secondaryinductance.

FIG. 56 is a cross section view of the PM transformer assembly where ahigh voltage laminate is applied at the interface between the primaryand secondary windings. This diagram simply depicts four total windinglayers. The number of winding layers implemented is determined by thedesired electrical specifications. What's important is that the primarywindings are layered on one half of the layer stack and the secondarywinding are layered on the other half, with a high voltage insulatinglaminate material applied in between.

While there has been illustrated and/or described what are presentlyconsidered to be example embodiments of claimed subject matter, it willbe understood by those skilled in the art that various othermodifications may be made, and/or equivalents may be substituted,without departing from the true scope of claimed subject matter.Additionally, many modifications may be made to adapt to a particularsituation to the teachings of claimed subject matter without departingfrom subject matter that is claimed. Therefore, it is intended that thepatent not be limited to the particular embodiments disclosed, but thatit covers all embodiments falling within the scope of the appendedclaims.

What is claimed is:
 1. An embedded high voltage magnetic devicecomprising: a base substrate defining a first base surface and a secondbase surface opposite and coplanar with the first base surface, the basesubstrate capturing a magnetic core between the first base surface andthe second base surface; a first conductive pattern disposed on at leasta portion of the first base surface; a second conductive patterndisposed on at least a portion of the second base surface, the firstconductive pattern being in operable alignment with the secondconductive pattern, wherein the first conductive pattern and the secondconductive pattern are coupled in electrical communication to define oneor more winding-type electric circuits surrounding the magnetic core toinduce a magnetic flux within the magnetic core when the first andsecond conductive patterns are energized by a voltage source; and thebase substrate being at least partially covered with a laminate materialhaving a higher breakdown voltage than the base substrate to preventvoltage breakdown between the first and second conductive patterns andthe surrounding atmosphere.
 2. The embedded high voltage magnetic deviceof claim 1 wherein the laminate material is formulated using both highvoltage and low voltage laminate materials to achieve a specific voltageisolation.
 3. The embedded high voltage magnetic device of claim 1wherein the one or more winding-type electric circuits define a twolayer embedded magnetic transformer that is bifilar wound.
 4. Theembedded high voltage magnetic device of claim 1 wherein the one or morewinding-type electric circuits define a two layer embedded magnetictransformer that is sector wound.
 5. The embedded high voltage magneticdevice of claim 1 wherein the one or more winding-type electric circuitsdefine a four layer embedded magnetic transformer that is bifilar wound.6. The embedded high voltage magnetic device of claim 1 wherein the oneor more winding-type electric circuits define a four layer embeddedmagnetic transformer that is sector wound.
 7. The embedded high voltagemagnetic device of claim 1 wherein the laminate material is of a typefrom the group consisting of: a polyimide cover-lay, a polymer soldermask, and FR-4 laminate.
 8. The embedded high voltage magnetic device ofclaim 1 wherein the first conductive pattern and the second conductivepattern are coupled in electrical communication using via arrays spacedto achieve a specific voltage isolation.
 9. The embedded high voltagemagnetic device of claim 8 wherein the via arrays are separated by aspecific distance to provide a pre-defined voltage isolation between thevia arrays.
 10. The embedded high voltage magnetic device of claim 1wherein the first conductive pattern and the second conductive patternare separated by a pre-defined distance to provide a specific voltageisolation.
 11. The embedded high voltage magnetic device of claim 1wherein the one or more winding-type electric circuits define a fourlayer embedded magnetic transformer wherein the first conductive patternis on the first and fourth layer and the second conductive pattern is onthe second and third layer.
 12. The embedded high voltage magneticdevice of claim 1 including a high voltage laminate material layerplaced between the first and second conductive patterns to achieve aspecific voltage isolation while minimizing the thickness of theembedded high voltage magnetic device.
 13. The embedded high voltagemagnetic device of claim 1 wherein the magnetic core is a square shapedferromagnetic core with two window areas.
 14. A planar embedded highvoltage magnetic device comprising: a base substrate defining a firstbase surface and a second base surface opposite and coplanar with thefirst base surface, the base substrate being captured within a magneticcore; a first conductive pattern disposed on at least a portion of thefirst base surface; a second conductive pattern disposed on at least aportion of the second base surface, the first conductive pattern beingin operable alignment with the second conductive pattern, wherein thefirst conductive pattern and the second conductive pattern are coupledin electrical communication to define one or more winding-type electriccircuits to induce a magnetic flux within the magnetic core when thefirst and second conductive patterns are energized by a voltage source;and the first base surface and the second base surface being separatedby a laminate material having a higher breakdown voltage than the basesubstrate to prevent voltage breakdown between the first and secondconductive patterns.
 15. The planar embedded high voltage magneticdevice of claim 14 wherein the laminate material is formulated usingboth high voltage and low voltage laminate materials to achieve aspecific voltage isolation.
 16. The planar embedded high voltagemagnetic device of claim 14 wherein the one or more winding-typeelectric circuits define a planer transformer having four or morelayers.
 17. The planar embedded high voltage magnetic device of claim 14wherein the laminate material is of a type from the group consisting of:a polyimide cover-lay, a polymer solder mask, and FR-4 laminate.